Single component inorganic/organic network materials and precursors thereof

ABSTRACT

Single component inorganic/organic network materials incorporating the physical properties of glasses with the flexibility of organic materials of empirical formula X(SiO1.5)n wherein X is one or more flexible organic linkages and n is greater than or equal to 2, as well as precursors thereof, are disclosed.

This is a continuation-in-part of application Ser. No. 07/945,777 filedSep. 16, 1992, now abandoned.

This invention concerns single component inorganic/organic materialswhich consist essentially of a multicomponent network comprisingflexible organic and rigid inorganic portions.

A significant limitation on both the generation and utility of inorganicnetwork materials such as glasses and ceramics relates to theirbrittleness. When glasses are prepared at room temperatures usingsol-gel technology, Brinker, C. J., et al., Sol Gel Science, AcademicPress, San Diego, Calif. (1990) drying stresses cause catastrophicfracture of films more than about 0.5 micron in thickness (for fullydense silica); larger monolithic structures are possible only with lowdrying rates. Applications for inorganic glasses are limited to those inwhich considerable amounts of energy absorption or dissipation (i.e.,toughness) are not required.

Prior attempts to make the glass network more compliant have involvedlimiting the number of networking bonds per silicon atom (e.g., usingalkyl(trialkoxy) silanes instead of tetraalkoxy silanes). There isgrowing interest in inorganic/organic hybrid materials which incorporateboth glasses and flexible organic material. One approach has been toincorporate organic polymers into silica glasses.

K. J. Shea et al., Chemistry of Materials, 1, 572(1989), discloseorganically modified silicates prepared by sol-gel processing ofbis-triethoxysilylaryl and bis-trichlorosilylaryl monomers. The threemonomers employed had the aryl portion of the monomer as phenylene (--C₆H₄ --), biphenylene (--C₆ H₄ -C₆ H₄ --), and triphenylene (--C₆ H₄ -C₆H₄ -C₆ H₄ --). Rigid networks are produced which are brittle, porous andcontain a single rigid organic link between silicon atoms.

The present invention comprises a new class of network materials whichincorporate both glasses and flexible organic materials withoutsuffering the deficiencies of the glasses produced by conventionalsol-gel technology. This invention concerns certain compositions havingchemically bonded inorganic network portions and organic networkportions. These two portions may be derived from a single precursormolecule or from a mixture of precursor molecules, which precursormolecules contain the elements of, or precursors to the elements of,both the inorganic and organic portions. Because both the organic andinorganic portions of the composition derive from the same precursormolecule, or from a mixture of such precursor molecules, the portionscannot be separated without the breaking of chemical bonds.

SUMMARY OF THE INVENTION

This invention comprises an inorganic/organic composition of theidealized empirical formula (II):

    X(SiO.sub.1.5).sub.n                                       (II)

wherein

n is an integer greater than or equal to 2; and

X is at least one flexible organic link selected from the groupconsisting of:

(a) R¹ _(m) SiY_(4-m) ;

(b) ring structures ##STR1## (c) R¹ _(m) Si(OSi(CH₃)₂ Y)_(4-m) ; (d) R¹_(m) Si(OY)_(4-m) ;

(e) CH₃ SiY₂ --O--SiY₂ CH₃ ;

(f) Y(CH₃)₂ Si--C₆ H₄ --Si(CH₃)₂ Y;

(g) O[--C₆ H₄ --Si(CH₃)₂ Y]₂ ;

(h) O[Si(CH₃)₂ Y]₂ ;

(i) Y(CH₃)₂ SiCH₂ --CH₂ Si(CH₃)₂ Y;

(j) Y(CF₂)_(p) Y, provided that when p is 6, Y is other than ethylene;

(k) Y₃ SiOSiY₃ ;

(l) Y₃ Si(CH₂)_(b) SiY₃ ; and

(m) Y₃ SiC₆ H₄ SiY₃ ;

(n) substituted benzene, including all isomers, selected from the groupconsisting of:

(i) C₆ H₃ (SiZ_(3-a) Y_(a))₃ ;

(ii) C₆ H₂ (SiZ_(3-a) Y_(a))₄ ;

(iii) C₆ H(SiZ_(3-a) Y_(a))₅ ; and

(iv) C₆ (SiZ_(3-a) Y_(a))₆ ; and

(o) substituted cyclohexane, including all stereoisomers, selected fromthe group consisting of:

(i) 1,2-C₆ H₁₀ (Y)₂ ; 1,3-C₆ H₁₀ (Y)₂ ; 1,4-C₆ H₁₀ (Y)₂

(ii) 1,2,4-C₆ H₉ (Y)₃ ; 1,2,3-C₆ H₉ (Y)₃ ; 1,3,5-C₆ H₉ (Y)₃ ;

(iii) 1,2,3,4-C₆ H₈ (Y)₄ ; 1,2,4,5-C₆ H₈ (Y)₄ ; 1,2,3,5-C₆ H₈ (Y)₄ ;

(iv) 1,2,3,4,5-C₆ H₇ (Y)₅ ; and

(v) C₆ H₆ (Y)₆ ;

wherein:

Z is an alkyl group of 1 to 4 carbon atoms, 3,3,3-trifluoropropyl,aralkyl, or aryl;

Y is (CR² R³)_(k) CR⁴ R⁵ CR⁶ R⁷ (CR⁸ R⁹)_(h) --;

R¹ is alkyl of 1 to about 8 carbon atoms or aryl;

R² to R⁹ are each independently hydrogen, alkyl of 1 to about 8 carbonatoms or aryl, provided that at least one of R⁴ to R⁷ is hydrogen;

m is 0, 1 or 2;

k and h are each independently an integer from 0 to 10, provided that atleast one of k or h is zero;

a is 1, 2 or 3;

p is an even integer from 4 to 10; and

b is an integer from 1 to 10.

This invention also comprises:

a compound of the formula (I):

    X(SiQ.sub.3).sub.n                                         (I)

wherein:

Q is alkoxy of 1 to about 8 carbon atoms, acyloxy of 1 to about 8 carbonatoms, or halogen;

n is an integer greater than or equal to 2; and

X is at least one flexible organic link selected from the groupconsisting of:

(a) R¹ _(m) SiY_(4-m) ;

(b) ring structures ##STR2## provided that when X is ##STR3## Z is otherthan methyl and Y is other than ethylene or propylene; and when X is##STR4## Z is other than methyl and Y is other than ethylene orpropylene;

(c) R¹ _(m) Si(OSi(CH₃)₂ Y)_(4-m) ;

(d) R¹ _(m) Si(OY)_(4-m) ;

(e) CH₃ SiY₂ --O--SiY₂ CH₃ ;

(f) Y(CH₃)₂ Si--C₆ H₄ --Si(CH₃)₂ Y; provided that in the definition of Yas defined below either h or k is greater than zero when Q is ethoxy;

(g) O[--C₆ H₄ --Si(CH₃)₂ Y]₂ ;

(h) O[Si(CH₃)₂ (Y)]₂ ; provided that in the definition of Y as definedbelow either h or k is greater than zero when Q is ethoxy;

(i) Y(CH₃)₂ SiCH₂ --CH₂ Si(CH₃)₂ Y;

(j) Y(CF₂)_(p) Y, provided that Y is other than ethylene;

(k) Y₃ SiOSiY₃ ;

(l) Y₃ Si(CH₂)_(b) SiY₃ ;

(m) Y₃ SiC₆ H₄ SiY₃ ;

(n) substituted benzene, including all isomers, selected from the groupconsisting of:

(i) C₆ H₃ (SiZ_(3-a) Y_(a))₃ ;

(ii) C₆ H₂ (SiZ_(3-a) Y_(a))₄ ;

(iii) C₆ H(SiZ_(3-a) Y_(a))₅ ; and

(iv) C₆ (SiZ_(3-a) Y_(a))₆ ; and

(o) substituted cyclohexane, including all stereoisomers, selected fromthe group consisting of:

(i) 1,2-C₆ H₁₀ (Y)₂ ; 1,3-C₆ H₁₀ (Y)₂ ; 1,4--C₆ H₁₀ (Y)₂ ;

(ii) 1,2,4-C₆ H₉ (Y)₃ ; 1,2,3-C₆ H₉ (Y)₃ ; 1,3,5-C₆ H₉ (Y)₃ ;

(iii) 1,2,3,4-C₆ H₈ (Y)₄ ; 1,2,4,5-C₆ H₈ (Y)₄ ; 1,2,3,5-C₆ H₈ (Y)₄ ;

(iv) 1,2,3,4,5-C₆ H₇ (Y)₅ ; and

(v) C₆ H₆ (Y)₆ ;

wherein:

Z is an alkyl group of 1 to 4 carbon atoms, 3,3,3-trifluoropropyl,aralkyl or aryl;

Y is (CR² R³)_(k) CR⁴ R⁵ CR⁶ R⁷ (CR⁸ R⁹)_(h) --;

R¹ is alkyl of 1 to about 8 carbon atoms or aryl;

R² to R⁹ are each independently hydrogen, alkyl of 1 to about 8 carbonatoms or aryl, provided that at least one of R⁴ to R⁷ is hydrogen;

m is 0, 1 or 2;

k and h are each independently an integer from 0 to 10, provided that atleast one of k or h is zero;

a is 1, 2 or 3;

p is an even integer from 4 to 10; and

b is an integer from 1 to 10.

This invention further comprises a compound of the formula III(j)':

    (SiQ.sub.3).sub.n CH.sub.2 CH.sub.2 (CF.sub.2).sub.p CH.sub.2 CH.sub.2 (SiQ.sub.3).sub.n                                         III(j)'

wherein:

Q is alkoxy of 1 to about 8 carbon atoms, acyloxy of 1 to about 8 carbonatoms, or halogen;

n is an integer greater than or equal to 2;

and p is an even integer from 4 to 10.

This invention further comprises a process for the preparation of acompound of formula (I), X(SiQ₃)_(n), as defined above comprisingreacting a compound containing an Si-H group with a compound containingan olefinic or alkynyl bond in the presence of a transition metalcatalyst such as platinum, or a free-radical initiator.

This invention further comprises a method for modifying sol-gel glassescomprising:

(a) combining a star gel precursor compound of formula (III), X(SiQ₃)_(n) wherein

Q is alkoxy of 1 to about 8 carbon atoms, acyloxy of 1 to about 8 carbonatoms, or halogen;

n is an integer greater than or equal to 2; and

X is at least one flexible organic link selected from the groupconsisting of:

(a) R¹ _(m) SiY_(4-m) ;

(b) ring structures ##STR5## (c) R¹ _(m) Si(OSi(CH₃)₂ Y)_(4-m) ;

(d) R¹ _(m) Si(OY)_(4-m) ;

(e) CH₃ SiY₂ --O--SiY₂ CH₃ ;

(f) Y(CH₃)₂ Si--C₆ H₄ --Si(CH₃)₂ Y;

(g) O[--C₆ H₄ --Si(CH₃)₂ Y]₂ ;

(h) O[Si(CH₃)₂ Y]₂ ;

(i) Y(CH₃)₂ SiCH₂ --CH₂ Si(CH₃)₂ Y;

(j) Y(CF₂)_(p) Y;

(k) Y₃ SiOSiY₃ ;

(l) Y₃ Si(CH₂)_(b) SiY₃ ; and

(m) Y₃ SiC₆ H₄ SiY₃ ;

(n) substituted benzene, including all isomers, selected from the groupconsisting of:

(i) C₆ H₃ (SiZ_(3-a) Y_(a))₃ ;

(ii) C₆ H₂ (SiZ_(3-a) Y_(a))₄ ;

(iii) C₆ H(SiZ_(3-a) Y_(a))₅ ; and

(iv) C₆ (SiZ_(3-a) Y_(a))₆ ; and

(o) substituted cyclohexane, including all stereoisomers, selected fromthe group consisting of:

(i) 1,2-C₆ H₁₀ (Y)₂ ; 1,3-C₆ H₁₀ (Y)₂ ; 1,4-C₆ H₁₀ (Y)₂ ;

(ii) 1,2,4-C₆ H₉ (Y)₃ ; 1,2,3-C₆ H₉ (Y)₃ ; 1,3,5-C₆ H₉ (Y)₃ ;

(iii) 1,2,3,4-C₆ H₈ (Y)₄ ; 1,2,4,5-C₆ H₈ (Y)₄ ; 1,2,3,5-C₆ H₈ (Y)₄ ;

(iv) 1,2,3,4,5-C₆ H₇ (Y)₅ ; and

(v) C₆ H₆ (Y)₆ ;

wherein:

Z is an alkyl group of 1 to 4 carbon atoms, 3,3,3-trifluoropropyl,aralkyl, or aryl;

Y is (CR² R³)_(k) CR⁴ R⁵ CR⁶ R⁷ (CR⁸ R⁹)_(h) --;

R¹ is alkyl of 1 to about 8 carbon atoms or aryl;

R² to R⁹ are each independently hydrogen, alkyl of 1 to about 8 carbonatoms or aryl, provided that at least one of R⁴ to R⁷ is hydrogen;

m is 0, 1 or 2;

k and h are each independently an integer from 0 to 10, provided that atleast one of k or h is zero;

a is 1, 2 or 3;

p is an even integer from 4 to 10; and

b is an integer from 1 to 10;

with a metal alkoxide sol-gel precursor;

(b) mixing in water with a solvent and a catalyst or a carboxylic acidoptionally in the presence of a solvent; and

(c) drying.

The resulting modified sol-gel glass can tolerate increased drying ratesand shows lower brittleness compared to the corresponding unmodifiedsol-gel glass.

This invention further comprises a process for the preparation of thecomposition of formula (II) as defined above comprising:

(a) mixing at least one compound of formula (I) or formula (III) asdefined above with water in the presence of a solvent and a catalyst, orwith at least one strong carboxylic acid having a pKa value of a maximumof about 4.0 and containing from 0 to 20 mole % water;

(b) maintaining the mixture resulting from step (a) at a temperaturewithin the range of about 0°-100° C.; and

(c) isolating the resulting inorganic/organic composition of formula(II).

This invention further comprises a method for coating a substratecomprising reacting the star gel precursor of formula (III), as definedabove, with water in the presence of a solvent and a catalyst, or astrong carboxylic acid optionally in the presence of a solvent, dippingthe substrate in the resulting mixture, removing the coated substratefrom the mixture, and drying the coating to generate a substrate coatedwith a composition of formula II, as defined above.

DETAILED DESCRIPTION OF THE INVENTION

This invention provides certain inorganic/organic compositionscomprising inorganic network portions and organic network portions.These two portions are derived from a single precursor molecule, or froma mixture of precursor molecules, which precursor molecules contain theelements of, or precursors to the elements of, both the inorganic andorganic portions. Because both the organic and inorganic portions of thecomposition derive from the same precursor molecule, or from a mixtureof such precursor molecules, the composition cannot be separated withoutthe breaking of chemical bonds.

The present invention further comprises a method for modifyingconventional sol-gel glasses to increase drying rates and lowerbrittleness comprising combining a star gel precursor of the presentinvention of formula (I) or formula (III) with a conventional sol-gelsystem based on tetraalkoxysilanes or other metal alkoxides; mixing inwater with a solvent and a catalyst, or a carboxylic acid optionally inthe presence of a solvent; and drying.

The inorganic/organic network compositions of the present invention,which can be in the form of gels or glasses, are of the idealizedempirical formula (II):

    X(SiO.sub.1.5).sub.n                                       (II)

as defined above wherein X is one or more flexible organic links, whichsimultaneously interconnect n silicon atoms where n is an integergreater than or equal to 2. Each of the latter atoms will beconstituents of a network structure via bonds to other silicon atomsthrough oxygen. For example, an inorganic/organic gel formed from Star 1(claim 1, (a)) which is X(SiO₁.5)_(n) wherein X=Si(CH₂ CH₂ --)₄, Y=--CH₂CH₂ --, m=0 and n=4 and the Si's of the Si--O--Si crosslinks are shownin standard print and the Si's of X in italics, could be represented asfollows: ##STR6##

Condensation to form Si--O--Si cross links from Si--OC₂ H₅ by hydrolysisdoes not go to 100% completion; this is shown above by residual,uncrosslinked SiOC₂ H₅ or SiOH groups. An idealized formula correspondsto 100% crosslinking. The idealized empirical formula of theinorganic/organic gel derived from Star 1 as shown above would be:Si(CH₂ CH₂ SiO₁.5)₄ -- the unit within the two half circles which bisectthe oxygen atoms.

The number of SiO₁.5 groups depend on the number of Y's as defined informula (I), (II) or (III). On the average there are 1.5 oxygensassociated with each Si. For example, when there are two Y's there are 2Si's. Every Y is attached to a Si; there are no unsatisfied valences.There will be --OR or --OH groups that are not crosslinked which isdesirable on the perimeter of the network for reacting with componentsin other compositions.

These compositions are prepared by the hydrolysis of one or more stargel precursors of the present invention of formula (I) or formula (III).Star gel precursors are molecules which comprise a flexible organic orinorganic core comprising a central atom, ring or short linear segmentlinked to multiple arms which terminate in a silicon atom which bears atleast two hydrolyzable substituents. The star gel precursors of thepresent invention comprise compounds of formula (I)

    x(SiQ.sub.3).sub.n                                         (I)

wherein X is at least one flexible organic link, as defined below, n isan integer greater than or equal to 2, and Q is a hydrolyzable groupsuch as alkoxy containing from 1 to about 8 carbon atoms, acyloxy of 1to about 8 carbon atoms, or halogen.

In general for formula (I), X comprises a central atom, ring or shortlinear segment with a number of arms which terminate in a silicon atom.In particular X comprises one or more flexible organic links selectedfrom the group consisting of:

(a) R¹ _(m) SiY_(4-m) ;

(b) ring structures ##STR7## provided that when X is ##STR8## Z is otherthan methyl and Y is other than ethylene or propylene; and when X is##STR9## Z is other than methyl and Y is other than ethylene orpropylene;

(c) R¹ _(m) Si(OSi(CH₃)₂ ^(Y))_(4-m) ;

(d) R¹ _(m) Si(OY)_(4-m) ;

(e) CH₃ SiY₂ --O--SiY₂ CH₃ ;

(f) Y(CH₃)₂ Si--C₆ H₄ --Si(CH₃)₂ Y; provided that in the definition of Yas defined below either h or k is greater than zero when Q is ethoxy;

(g) O[--C₆ H₄ --Si(CH₃)₂ Y]₂ ;

(h) O[Si(CH₃)₂ Y]₂ ; provided that in the definition of Y as definedbelow either h or k is greater than zero when Q is ethoxy;

(i) Y(CH₃)₂ SiCH₂ --CH₂ Si(CH₃)₂ Y;

(j) Y(CF₂)_(p) Y, provided that Y is other than ethylene;

(k) Y₃ SiOSiY₃ ;

(l) Y₃ Si(CH₂)_(b) SiY₃ ;

(m) Y₃ SiC₆ H₄ SiY₃ ;

(n) substituted benzene, including all isomers selected from the groupconsisting of:

(i) C₆ H₃ (SiZ_(3-a) Y_(a))₃ ;

(ii) C₆ H₂ (SiZ_(3-a) Y_(a))₄ ;

(iii) C₆ ^(H) (SiZ_(3-a) Y_(a))₅ ; and

(iv) C₆ (SiZ_(3-a) Y_(a))₆ ; and

(o) substituted cyclohexane, including all stereoisomers, selected fromthe group consisting of:

(i) 1,2-C₆ H₁₀ (Y)₂ ; 1,3-C₆ H₁₀ (Y)₂ ; 1,4-C₆ H₁₀ (Y)₂ ;

(ii) 1,2,4-C₆ H₉ (Y)₃ ; 1,2,3-C₆ H₉ (Y)₃ ; 1,3,5-C₆ H₉ (Y)₃ ;

(iii) 1,2,3,4-C₆ H₈ (Y)₄ ; 1,2,4,5-C₆ H₈ (Y)₄ ; 1,2,3,5-C₆ H₈ (Y)₄ ;

(iv) 1,2,3,4,5-C₆ H₇ (Y)₅ ; and

(v) C₆ H₆ (Y)₆ ;

wherein:

Z is an alkyl group of 1 to 4 carbon atoms, 3,3,3-trifluoropropyl,aralkyl or aryl;

Y is (CR² R³)_(k) CR⁴ R⁵ CR⁶ R⁷ (CR⁸ R⁹)_(h) --;

R¹ is alkyl of 1 to about 8 carbon atoms or aryl;

R² to R⁹ are each independently hydrogen, alkyl of 1 to about 8 carbonatoms or aryl, provided that at least one of R⁴ to R⁷ is hydrogen;

m is 0, 1 or 2;

k and h are each independently an integer from 0 to 10, provided that atleast one of k or h is zero;

a is 1, 2 or 3;

p is an even integer from 4 to 10; and

b is an integer from 1 to 10.

For formula (I), (II) and (III) the most preferred flexible organiclink, X, is where m is 0, k is 0 or 1, h is 0 or 1, and all of R² to R⁹are hydrogen. The preferred Q are alkoxy of 1 to about 3 carbon atoms.Most preferred Q is ethoxy. The most preferred halogen is chloro. Thepreferred aralkyl is benzyl. The preferred aryl is phenyl.

Preferred star gel precursors of formula III include those listed inTable I below.

                                      TABLE I                                     __________________________________________________________________________    Star-Gel Precursors                                                           __________________________________________________________________________    Star 1:                                                                            Si(CH.sub.2 CH.sub.2 Si(OC.sub.2 H.sub.5).sub.3).sub.4                   Star 2:                                                                             ##STR10##                                                               Star 3:                                                                            Si[OSi(CH.sub.3).sub.2 CH.sub.2 CH.sub.2 Si(OC.sub.2 H.sub.5).sub.3           ].sub.4                                                                  Star 4:                                                                            Si(OCH.sub.2 CH.sub.2 CH.sub.2 Si(OC.sub.2 H.sub.5).sub.3).sub.4         Star 5:                                                                             ##STR11##                                                               Star 6:                                                                             ##STR12##                                                               Star 7:                                                                             ##STR13##                                                               Star 8:                                                                             ##STR14##                                                               Star 9:                                                                             ##STR15##                                                               Star 10:                                                                            ##STR16##                                                               Star 11:                                                                           Si(CH.sub.2 CH.sub.2 CH.sub.2 Si(OC.sub.2 H.sub.5).sub.3).sub.4          Star 12:                                                                            ##STR17##                                                               Star 13:                                                                            ##STR18##                                                               Star 14:                                                                           Si[OSi(CH.sub.3).sub.2 CH.sub.2 CH.sub.2 CH.sub.2 Si(OC.sub.2                 H.sub.5).sub.3 ].sub.4                                                   Star 15:                                                                            ##STR19##                                                               Star 16:                                                                           (C.sub.2 H.sub.5 O).sub.3 SiCH.sub.2 CH.sub.2 (CF.sub.2).sub.p                CH.sub.2 CH.sub.2 Si(OCH.sub.2 H.sub.5).sub.3                            Star 17:                                                                           CH.sub.3 Si[OSi(CH.sub.3).sub.2 CH.sub.2 CH.sub.2 Si(OCH.sub.2                H.sub.5).sub.3 ].sub.3                                                   Star 18:                                                                           Si[CH.sub.2 CH.sub. 2 Si(OCH.sub.3).sub.3 ].sub.4                        Star 19:                                                                            ##STR20##                                                               Star 20:                                                                            ##STR21##                                                               Star 21:                                                                           (C.sub.2 H.sub.5 O).sub.3 Si(CH.sub.2).sub.6 (CF.sub.2).sub.10                (CH.sub.2).sub.6 Si(OC.sub.2 H.sub.5).sub.3                              Star 22:                                                                            ##STR22##                                                               __________________________________________________________________________

Preferred star gel precursors of formula I include Stars 1, 3, 4, 5, 7,9, 11, 13, 14, 15, 17, 18, 19, 20, 21, and 22 as shown in Table I.

The present invention also comprises a compound of the formula III(j)':

    (SiQ.sub.3).sub.n CH.sub.2 CH.sub.2 (CF.sub.2).sub.p CH.sub.2 CH.sub.2 (SiQ.sub.3).sub.n                                         III(j)'

wherein:

Q is alkoxy of 1 to about 8 carbon atoms, acyloxy of 1 to about 8 carbonatoms, or halogen;

n is an integer greater than or equal to 2; and

p is an even integer from 4 to 10.

Q is preferably ethoxy or C₁. p is preferably 6 or 10.

The present invention further comprises processes for preparation ofstar gel precursors of formula I as defined above.

Synthesis of the star gel precursors is afforded from hydrosilylationreactions, i.e. an addition reaction between a compound containing aSi-H group with a compound containing aliphatic unsaturation (C═C or--C.tbd.C--) in the presence of a catalyst or free radical initiator.Precursor segments containing --CH═CH₂ groups react with other precursorsegments which contain terminal Si-H bonds. With these precursorsegments a number of different flexible star gel precursors can beconstructed as illustrated in Table 1.

Either precursor segment may contain the vinyl or other unsaturatedgroup capable of Si-H addition. For example, Si(CH═CH₂)₄ reacts withHSi(OC₂ H₅)₃ to form star gel precursor 1, Si[CH₂ CH₂ Si(OC₂ H₅)₃ ]₄ ;and cyclo[(CH₃)HSiO]₅ reacts with CH₂ ═CH--Si(OC₂ H₅)₃ to form star gelprecursor 10, cyclo [OSi(CH₃)CH₂ CH₂ Si(OC₂ H₅)₃ ]₅.

All of the following equations with the exception of Equations 7B and 7Cprovide for preparation of compounds of formula I by addition of asilane across a carbon-carbon double bond for various definitions of X:

(a) when X is R¹ _(m) Si[Y]_(4-m) :

    R.sup.1.sub.m Si[(CR.sup.2 R.sup.3).sub.k CR.sup.4 =CR.sup.6 R.sup.7 ].sub.4-m +4-mH(CR.sup.8 R.sup.9).sub.h SiQ.sub.3 →

    R.sup.1.sub.m Si[(CR.sup.2 R.sup.3).sub.k CR.sup.4 R.sup.5 CR.sup.6 R.sup.7 (CR.sup.8 R.sup.9).sub.h SiQ.sub.3 ].sub.4-m              Eqn. 1A

    or

    R.sup.1.sub.m Si[(CR.sup.2 R.sup.3).sub.k H].sub.4-m +4-mCR.sup.4 R.sup.5 =CR.sup.6 (CR.sup.8 R.sup.9).sub.h SiQ.sub.3 →

    R.sup.1.sub.m Si[(CR.sup.2 R.sup.3).sub.k CR.sup.4 R.sup.5 CR.sup.6 R.sup.7 (CR.sup.8 R.sup.9).sub.h SiQ.sub.3 ].sub.4-m              Eqn. 1B

(b) when X is a ring structure of the type Ia, Ib or Ic as previouslydefined which can be abbreviated (SiO)_(u) Z_(u) (YSiQ₃)_(u), whereinu=3 for Ia, u=4 for Ib, and u=5 for Ic; then

    (SiO).sub.u Z.sub.u [(CR.sup.2 R.sup.3).sub.k CR.sup.4 =CR.sup.6 R.sup.7 ].sub.u +.sub.u H(CR.sup.8 R.sup.9).sub.h SiQ.sub.3 →

    (SiO).sub.u Z.sub.u [(CR.sup.2 R.sup.3).sub.k CR.sup.4 R.sup.5 CR.sup.6 R.sup.7 (CR.sup.8 R.sup.9).sub.h SiQ.sub.3 ].sub.u        Eqn. 2A

    (SiO).sub.u Z.sub.u [(CR.sup.2 R.sup.3).sub.k H].sub.u +.sub.u CR.sup.4 R.sup.5 =CR.sup.6 (CR.sup.8 R.sup.9).sub.h SiQ.sub.3 →

    (SiO).sub.u Z.sub.u [(CR.sup.2 R.sup.3).sub.k CR.sup.4 R.sup.5 CR.sup.6 R.sup.7 (CR.sup.8 R.sup.9).sub.h SiQ.sub.3 ].sub.u        Eqn. 2B

(c) when X is R¹ _(m) Si[OSi(CH₃)₂ Y]_(4-m) :

    R.sup.1.sub.m Si[OSi(CH.sub.3).sub.2 (CR.sup.2 R.sup.3).sub.k CR.sup.4 =CR.sup.6 R.sup.7 ].sub.4-m +4-mH(CR.sup.8 R.sup.9).sub.h SiQ.sub.3 →

    R.sup.1.sub.m Si[OSi(CH.sub.3).sub.2 (CR.sup.2 R.sup.3).sub.k CR.sup.4 R.sup.5 CR.sup.6 R.sup.7 (CR.sup.8 R.sup.9).sub.h SiQ.sub.3 ].sub.4-m Eqn. 3A

    or

    R.sup.1.sub.m Si[OSi(CH.sub.3).sub.2 (CR.sup.2 R.sup.3).sub.k H].sub.4-m +4-mCR.sup.4 R.sup.5 =CR.sup.6

     (CR.sup.8 R.sup.9).sub.h SiQ.sub.3 →

    R.sup.1.sub.m Si[OSi(CH.sub.3).sub.2 (CR.sup.2 R.sup.3).sub.k CR.sup.4 R.sup.5 CR.sup.6 R.sup.7 (CR.sup.8 R.sup.9).sub.h SiQ.sub.3 ].sub.4-m Eqn. 3B

(d) when X is R¹ _(m) Si[OY]_(4-m) :

    R.sup.1.sub.m Si[O(CR.sup.2 R.sup.3).sub.k CR.sup.4 =CR.sup.6 R.sup.7 ].sub.4-m +4-mH(CR.sup.8 R.sup.9).sub.h

     SiQ.sub.3 →

    R.sup.1.sub.m Si[O(CR.sup.2 R.sup.3).sub.k CR.sup.4 R.sup.5 CR.sup.6 R.sup.7 (CR.sup.8 R.sup.9).sub.h SiQ.sub.3 ].sub.4-m      Eqn. 4

(e) when X is CH₃ SiY₂ --O--SiY₂ CH₃ :

    CH.sub.3 Si((CR.sup.2 R.sup.3).sub.k CR.sup.4 =CR.sup.6 R.sup.7).sub.2 --O--Si((CR.sup.2 R.sup.3).sub.k CR.sup.4 =

     CR.sup.6 R.sup.7).sub.2 CH.sub.3 +4H(CR.sup.8 R.sup.9).sub.h SiQ.sub.3 →

    CH.sub.3 Si((CR.sup.2 R.sup.3).sub.k CR.sup.4 R.sup.5 CR.sup.6 R.sup.7 (CR.sup.8 R.sup.9).sub.h

    SiQ.sub.3).sub.2 --O--Si((CR.sup.2 R.sup.3).sub.k CR.sup.4 R.sup.5 CR.sup.6 R.sup.7

    (CR.sup.8 R.sup.9).sub.h

     SiQ.sub.3).sub.2 CH.sub.3                                 Eqn. 5

    or

    CH.sub.3 Si((CR.sup.2 R.sup.3).sub.k H).sub.2 --O--Si((CR.sup.2 R.sup.3).sub.k H).sub.2 CH.sub.3 +4 CR.sup.4 R.sup.5

     =CR.sup.6 (CR.sup.8 R.sup.9).sub.h SiQ.sub.3 →

    CH.sub.3 Si((CR.sup.2 R.sup.3).sub.k CR.sup.4 R.sup.5 CR.sup.6 R.sup.7 (CR.sup.8 R.sup.9).sub.h SiQ.sub.3).sub.2 --O--Si((CR.sup.2 R.sup.3).sub.k CR.sup.4 R.sup.5 CR.sup.6 R.sup.7 (CR.sup.8 R.sup.9).sub.h

     SiQ.sub.3).sub.2 CH.sub.3                                 Eqn. 5B

when X is

(f) Y(CH₃)₂ Si--C₆ H₄ --Si(CH₃)₂ Y;

(g) O[--C₆ H₄ --Si(CH₃)₂ Y]₂ ;

(h) O[Si(CH₃)₂ Y]₂ ; or

(i) Y(CH₃)₂ SiCH₂ CH₂ Si(CH₃)₂ Y

Formula I can generally be written as D (YSiQ₃)2 wherein Y is aspreviously defined and D is a connecting group chosen from: ##STR23##

then the product D(YSiQ₃)₂ is formed by the reaction

    D[(CR.sup.2 R.sup.3).sub.k CR.sup.4 =CR.sup.6 R.sup.7 --].sub.2 +2H(CR.sup.8 R.sup.9).sub.h SiQ.sub.3 →

    D[(CR.sup.2 R.sup.3).sub.k CR.sup.4 R.sup.5 CR.sup.6 R.sup.7 (CR.sup.8 R.sup.9).sub.h SiQ.sub.3 ].sub.2                          Eqn. 6A

    or

    D[(CR.sup.2 R.sup.3).sub.k H].sub.2 +2CR.sup.4 R.sup.5 =CR.sup.6 (CR.sup.8 R.sup.9).sub.h SiQ.sub.3 →

    D[(CR.sup.2 R.sup.3).sub.k CR.sup.4 R.sup.5 CR.sup.6 R.sup.7 (CR.sup.8 R.sup.9).sub.h SiQ.sub.3 ].sub.2                          Eqn. 6B

(j) when X is Y(CF₂)_(p) Y: ##STR24##

for k=0; p=4, 6 or 8; all R's=H:

    I(CF.sub.2).sub.p I+2CR.sup.4 R.sup.5 =CR.sup.6 (CR.sup.8 R.sup.9).sub.h SiQ.sub.3 →

    Q.sub.3 Si(CR.sup.9 R.sup.8).sub.h CR.sup.6 (I)CR.sup.5 R.sup.4 (CR.sup.2 R.sup.3).sub.k (CF.sub.2).sub.p

    (CR.sup.2 R.sup.3).sub.k CR.sub.4 R.sup.5 CR.sup.6 (I)(CR.sup.8 R.sup.9).sub.h SiQ.sub.3                                  Eqn. 7C

    Q.sub.3 Si(CR.sup.9 R.sup.8).sub.h CR.sup.6 (I)CR.sup.5 R.sup.4 (CR.sup.2 R.sup.3).sub.k (CF.sub.2).sub.p

    (CR.sup.2 R.sup.3).sub.k CR.sup.4 R.sup.5 CR.sup.6 (I)(CR.sup.8 R.sup.9).sub.h SiQ.sub.3

    can be converted to

    Q.sup.3 Si(CR.sup.9 R.sup.8).sub.h CR.sup.6 HCR.sup.5 R.sup.4 (CR.sup.2 R.sup.3).sub.k (CF.sub.2).sub.p

    (CR.sup.2 R.sup.3).sub.k CR.sup.4 R.sup.5 CR.sup.6 H(CR.sup.8 R.sup.9).sub.h SiQ.sub.3 by standard organic techniques, e.g., using samarium iodide.

(k) when X is Y₃ --Si--O--Si--Y₃ : ##STR25## (l) when X is Y₃--Si--(CH₂)_(b) --Si--Y³ : ##STR26## (m) when X is Y₃ --Si--C₆ H₄--Si--Y₃ : ##STR27## (n) when X is a substituted benzene structure ofthe type, as previously defined, which can be abbreviated C₆ H_(6-w)(SiZ_(3-a) Y_(a))_(w) :

    w×Q.sub.3 Si(CR.sup.8 CR.sup.9).sub.h +C.sub.6 H.sub.6-w [SiZ3-a((CR.sup.2 R.sup.3).sub.k CR.sup.4 =CR.sup.6 R.sup.7).sub.a ].sub.w →C.sub.6 →

    6-w[SiZ.sub.3-a ((CR.sup.2 R.sup.3).sub.k CR.sup.4 HCR.sup.6 R.sup.7 (CR.sup.8 R.sup.9).sub.h SiQ.sub.3).sub.a ].sub.w         Eqn. 11A

    or

    w×CR.sub.4 CR.sup.5 =CR.sup.6 (CR.sup.8 CR.sup.9).sub.h SiQ.sub.3 +C.sub.6 H.sub.6-w [SiZ.sub.3-a ((CR.sup.2 R.sup.3).sub.k H).sub.a ].sub.w →

    C.sub.6 H.sub.6-w [SiZ.sub.3-a ((CR.sup.2 R.sup.3).sub.k CR.sup.4 HCR.sup.6 R.sup.7 (CR.sup.8 R.sup.9).sub.h SiQ.sub.3).sub.a ].sub.w Eqn. 11B

(o) when X is a substituted cyclohexane structure of the type, aspreviously defined, which can be abbreviated C₆ H_(12-w) (Y)_(w),wherein w is the number of substituents; then

    C.sub.6 H.sub.12-w ((CR.sup.2 R.sup.3).sub.k CR.sup.4 =CR.sup.6 R.sup.7).sub.w +w[Q.sub.3 Si(CR.sup.8 R.sup.9).sub.h H]→

    C.sub.6 H.sub.12-w ((CR.sup.2 R.sup.3).sub.k CR.sup.4 HCR.sup.6 R.sup.7 (CR.sup.8 R.sup.9).sub.h SiQ.sub.3).sub.w

For convenience the reaction of Equations denoted A or B above is chosendepending upon the commercial availability of the starting reagents. Ineach set of equations where an A and B are presented, h=0 in Eqn. A andk=0 in Eqn. B. In (d), k=1 and h=0. Specific sources of reactants arelisted hereinafter just prior to the Examples. The reactants areemployed in a ratio such that the precursor containing the SiQ₃ group isemployed in a molar excess of 10-50% to ensure completion of thehydrosilylation reaction. A transition metal catalyst such as platinum,or a free radical initiator is employed in an effective amount. Examplesof suitable free radical initiators include VAZO® compounds availablefrom E. I. du Pont de Nemours and Company, Wilmington, Del.

These reactions can be conducted at a temperature of from about 25° C.to about 100° C. Preferably the process is conducted at about 80° C. toabout 100° C. The pressure employed is typically ambient, about 1 atm(1.01×10⁵ Pa). The reactions are carried out under an inert gasatmosphere, although use of an air atmosphere is not precluded. Reactiontime is typically from about 4 hours to about 24 hours.

Use of solvent is not required in these reactions. Suitable solventswhich may be employed are those capable of dissolving the reactants andwhich do not interfere with the reaction or generate unnecessaryby-products. The desired product can be isolated by any means known tothose skilled in the art. Preferably the desired product is isolated byremoval of volatiles under reduced pressure.

NMR and K⁺ IDS mass spectrometry have been used to characterize productpurities. Typically, yields of completely reacted material exceed 85%,with the principal impurities being either reverse (Markovnikov)hydrosilylation or incompletely substituted material containingunreacted --CH═CH₂ groups. The catalyst can be removed, by filteringthrough silica gel or activated charcoal.

Synthesis of the star gel precursors wherein X=Y(CF₂)_(p) Y may also beafforded from a metallation reaction between an alpha-omegadiiodoalkylperfluoroalkane, e.g., contacted with tert-butyl lithium,followed by reaction with Si(OEt)₄, as shown above in Equation 7B.Alternatively unsaturated trialkoxysilanes, or trihalosilanes can beinserted into the C-I bond of I(CF₂)_(p) I, followed by reduction of theC-I to C-H using standard organic reduction reagents as shown inEquation 7C. Examples of suitable reagents are zinc metal, tri-n-butyltin hydride or samarium iodide.

Possible uses of star gel precursors of the present invention are asmultifunctional cross-linkers for other sol-gel or polymeric systems,and very high surface area materials, i.e., aerogels, when dried viasupercritical fluid media. Although the openness of a structure such asstar gel precursor 1, Si[CH₂ CH₂ Si(OC₂ H₅)₃ ]₄, suggests that theresulting glass would have open porosity and very high surface area,pore collapse can occur during drying via simple solvent evaporationwhen the network is sufficiently flexible leading to non-porous coatingsor materials.

The present invention further comprises a process for the preparation ofan inorganic/organic composition of formula (II). To form thecomposition of formula (II) of the present invention as defined abovethe alkoxysilane, acyloxysilane or halosilane groups of the star gelprecursors of formula (I) or formula (III) as previously defined, arehydrolyzed with either water in the presence of a solvent and acatalyst, or one or more strong carboxylic acids, preferably formicacid, optionally in the presence of a solvent and condensed to form acontinuous network of silicon-oxygen bonds. The silicon atoms bearingthe hydrolyzed groups will be constituents of an infinite networkstructure via bonds to other silicon atoms through oxygen. Preferredstar gel precursors of formula I or formula III for use in this processinclude those listed in Table I.

The present invention also further comprises a method for preparingcompositions of glasses of formula II by combining two or more star gelprecursors of the present invention of formula (I) or formula III witheach other. If more than one compound of formula (I) or formula III, asdefined above, is mixed, the star gel precursors may be represented asX'(SiQ₃)_(n) '+X"(SiQ₃)_(n) "+. . . , wherein X' and X" are differentdefinitions of X and n' and n" correspond to the definitions of X' andX" respectively. The resulting inorganic/organic composition of formula(II), as defined above, will be X(SiO₁.5)_(n), where X=% X'+% X"+ . . .and n=average of (% n'+% n"+ . . . ). Star-derived glasses may also beproduced in the presence of a dye such as Rhodamine G to yield anoptically useful material.

The process of this invention has the desirable feature that no waterneed be added to the reactants initially and that the steady state waterconcentration during reaction can be quite small. One of the benefits ofthis feature is that clear gels can be made readily without a need touse a water-miscible solvent to obtain a homogeneous medium. While wateris necessary for hydrolysis, a sufficient amount is formed by reactionof strong carboxylic acid with alcohol produced by hydrolysis and by themetathesis reaction:

    HCOOH+--SiOR⃡--SiOOCH+ROH

Also, any water which may be present as diluent in strong carboxylicacid can contribute to hydrolysis. Strong carboxylic acid containing atmost 20 mol % water is preferred for the process of this invention. Thecarboxylic acids should have a pk_(a) value not higher than about 4.0and contain 0 to 20 mole % water. Examples of strong carboxylic acidseffective in this invention include formic acid, monochloroacetic acid,dichloroacetic acid, trifluoroacetic acid and hydroxyacetic acid. Formicacid is the preferred carboxylic acid. After the star gel precursor ismixed with water in the presence of a solvent and a catalyst, or thestrong carboxylic acid optionally in the presence of a solvent, themixture is maintained at a temperature within the range of about 0°-100°C. at ambient pressure. The star gel is finally isolated via removal ofliquid byproducts and unreacted starting materials to yield a glass.

When the star gel precursors of formula (I) or formula (III) arehydrolyzed with water in the presence of a solvent and a catalyst,suitable solvents comprise co-solvents for water and the star gelprecursor of formula (I) or formula (III) or are miscible with waterwith an affinity for the star gel precursor of formula (I) or formula(III), e.g., alcohols, tetrahydrofuran, and acetonitrile. Suitablecatalysts comprise Bronsted acids or weak bases where pH <9, e.g.,hydrogen fluoride, sodium fluoride, sulfuric acid, acetic acid andammonium hydroxide.

Those glasses of formula (II) prepared by drying the gels of formula(II) wherein the X component corresponds to a linear or cyclosiloxaneshow the greatest flexibility. This flexibility provides a morecompliant network structure. The compliance incorporated into thenetwork allows faster drying rates and imparts toughness to theresultant glasses prepared from gels of formula (II).

Star gel precursor 1, Si[CH₂ CH₂ Si(OC₂ H₅)₃ ]₄, star gel precursor 2,##STR28## and star gel precursor 3, Si[OSi(CH₃)₂ CH₂ CH₂ Si(OC₂ H₅)₃ ]₄,in Table 1 are readily soluble in tetrahydrofuran and mixtures of thatsolvent with water or formic acid. The latter, formic acid, has beendeveloped as a highly effective hydrolyric and condensation agent fortetraalkoxysilanes. Several star gel precursors, e.g., 3, can be addeddirectly to formic acid to give a dispersion which rapidly clarifies asthe molecule begins to react and silanol groups are generated. Gelationrates with formic acid can be extremely fast in the absence of solvent.Star gel precursor 3, Si[OSi(CH₃)₂ CH₂ CH₂ Si(OC₂ H₅)₃ ]₄ forms a gelwith a 20-fold molar excess of HCOOH in 6 minutes. The use of aH-bonding acceptor solvent such as tetrahydrofuran can attenuate thegelation rate up to several orders of magnitude. A less reactive solventsuch as methylene chloride will give a more rapid gelation rate than ahydrogen bonding solvent. Pure star gel precursors have long shelf life.Hydrolyric reagent and optional solvent and catalyst if water is usedare added to initiate the reaction. Gels are clear except for thecoloration imparted by any residual catalyst. They may be dried intomonolithic glassy solids at rates at least five times those which leadto fracture of conventional gels of the same dimensions. Thick films ofthese glasses can be easily dried without any observed cracking upondrying. In this manner films that are five times thicker than thosederived from sol-gel silica can be made crack free.

Dried samples of glass of formula (II) derived from star gel precursors1, 2 and 3 as defined above and in Table I, do not show evidence of openporosity when submerged under water. Adsorption isotherm measurementsusing nitrogen at 77° K. also indicated no detectable surface-connectedporosity for a sample of the glass derived from star gel precursor 1,Si[CH₂ CH₂ Si(OC₂ H₅)₃ ]₄.

Impact resistance was examined by dropping a 150 g pestle from variousheights onto pieces of star-derived and conventional sol-gel glasses ofcomparable size. The star glasses were able to sustain impacts whichinvariably fractured their conventional counterparts.

The new classes of compositions of formula (II), in addition to thosecited above, are useful as abrasion resistant materials, impactresistant glasses, microporous glasses, interlayer dielectrics forelectronic devices, adhesives for glass and other materials, and barriercoatings. Star gel precursors of formula (I), are useful as crosslinkingagents for some functionalized organic polymers, coupling agents, ormodifiers for alkoxysilane derived sol-gel glasses, other metal alkoxidederived sol-gel glasses, and other star-gel glasses.

The present invention further comprises a method for modifyingconventional sol-gel glasses as defined in Brinker, C. J., et al., SolGel Science, Academic Press, San Diego, Calif. (1990), to increasedrying rates and lower brittleness comprising combining a precursor ofthe present invention of formula (I) or of formula (III) with aconventional sol-gel system based on tetraalkoxysilanes or other metalalkoxides; mixing in water with a solvent and a catalyst, or acarboxylic acid, preferably formic acid, optionally in the presence of asolvent; and drying. The known tetralkoxysilane or other metal alkoxideis combined with a star gel precursor of the present invention,preferably the star gel precursors include those found in Table I, togenerate a homogenous solution. These components are miscible anduseable in any proportion, e.g., from 0.1:99.9 to 99.9:to 0.1. Waterwith a solvent and a catalyst, or a carboxylic acid, preferably formicacid, optionally in the presence of a solvent, is then added withstirring at ambient temperature and pressure to induce gelation. Theresulting gel is then dried. Typically drying is at atmospheric pressureand at a temperature of from about 20° C. to 150° C. Vacuum up to 10⁻⁵torr may be employed. The gelation rate of Si(OC₂ H₅)₄ by formic acidcan be profoundly influenced by addition of small amounts of a star gelprecursor of formula (I) or formula (III). A mixture of Si(OC₂ H₅)₄ andHCOOH at a molar ratio of 1:3 normally requires 18 hours to gel.Substitution of 10 mole % star gel precursor 1, Si[CH₂ CH₂ Si(OC₂ H₅)₃]₄, for Si(OC₂ H₅)₄ led to a gelation time of 8 minutes under comparableconditions. Other sol-gel glasses from inorganic alkoxides, for examplealkoxides of Al, Zr, V, B, Ti, Nb, Ge, Sn, Ga, In, Cu and Pb can bemodified in a similar fashion.

A method of coating a substrate is also provided by the presentinvention comprising reacting a star gel precursor of formula (I) orformula (III), preferably including those in Table I, with water in thepresence of a solvent and a catalyst, or a carboxylic acid, such asformic acid, optionally in the presence of a solvent, such astetrahydrofuran, dipping the substrate in the resulting mixture,removing the coated substrate from the mixture and drying the coating.Thus the substrate is dipped into the mixture containing the star gelprecursor prior to gelation, and after gelation and drying the substrateis coated with an inorganic/organic composition of formula (II). Thestar gel precursor of formula (I) or formula (III) or inorganic/organiccomposition of formula (II) may also be used as an adhesive by coating asubstrate and placing another substrate on top of it and applyingpressure, optionally accompanied by or followed by heat. Suitablesubstrates comprise glass, metal and plastic.

In the examples which follow all star numbers refer to the star gelprecursors listed in Table I. All reactions were carried out in a VacuumAtmospheres Co. dry box under nitrogen. Commercial reagents weredistilled prior to use. Triethoxysilane, tetravinylsilane,vinyltriethoxysilane, 1,3,5,7-tetramethylcyclotetrasilane,1,3,5,7-tetravinyltetramethylcyclotetrasilane,1,1,3,3-tetravinyldimethyldisiloxane, tetraallyloxysilane,tetrakis(dimethylsiloxy)silane, p-bis(dimethylsilyl)benzene,bis[p-dimethylsilyl)phenyl]ether, 1,1,3,3-tetramethyldisiloxane,1,1,4,4-tetramethyldisilethylene, pentamethylcyclopentasiloxane,methyltris(dimethylsiloxy)silane, chlorodimethylvinylsilane,tetraethoxysilane and trichlorosilane were purchased from Huls AmericaInc., Piscataway, N.J. Allyltriethoxsilane; trimethoxysilane;triethoxysilane, 1,3,5-tribromobenzene; 1,2,4-trivinylcyclohexane andtert-butyllithium (1.7M in pentane) were purchased from Aldrich ChemicalCol., Milwaukee, Wis. Tetraethoxysilane was purchased from EastmanKodak, Rochester, N.Y. Platinum divinylsiloxane complex (3-3.5% Ptconcentration in xylene, Huls PC072) was obtained from Huls America Inc.and diluted 5:1 by volume (toluene, Pt complex) prior to use. Cobaltcarbonyl and P(OCH₃)₃ were obtained from E. I. du Pont de Nemours andCompany. Toluene was reagent grade and purified by distillation fromlithium aluminum hydride prior to use. Tetrallylsilane was synthesizedby a modification of a published procedure (J. Organomet. Chem.,84(1975), pp. 199-299). 1,3,5-(CH₂ ═CH(CH₃)₂ Si)₃ C₆ H₃ was synthesizedby a modification of a published procedure using CH₂ ═CHCH₃)₂ SIClinstead of Si(OC₂ H₅)₄ (Macromolecules, 24 (1991), pp. 6863-6866). Thepreparation of silicon alkoxides (Si-OR) from chlorosilanes (Si-Cl) andalcohol was accomplished according to known procedures (OrganosiliconCompounds, C. Earborn, Academic Press Inc., NY, 1960, pp. 288-311).Vinylpolyfluoroalkanes CH₂ ═CH(CF₂)_(p) CH═CH₂ (p=6, 10), CH₂ ═CH(CH₂)₄(CF₂)₁₀ (CH₂)₄ CH═CH₂, and ICH₂ CH₂ (CF₂)₆ CH₂ I were obtained pure fromE. I. du Pont de Nemours and Company, Wilmington, Del. Normalpurification of the star gel precursors involved flash chromotography onsilica gel using hexane as the elutant unless otherwise noted. Thesilica gel column was treated with Si(OCH₃)₄ before addition of the stargel precursors. The K⁺ IDS mass specroscopy experiments were performedon a Finnigan 4615B GC/MS quadrupole mass spectrometer (San Jose,Calif.). An electron impact source configuration operating at 200° C.and a source pressure of 1.0×10⁻⁶ Torr was used. The mass spectrometerwas scanned at a rate of about 1000 Daltons/second. All K⁺ IDS massspectral peaks are recorded as sum of the ion plus potassium (M+39).Proton and carbon NMR were determined in deuterobenzene solvent on a GEmodel QE-300 instrument. Elemental analyses were performed by OneidaResearch Services Inc., One Halsey Road, Whitesboro, N.Y.

EXAMPLES EXAMPLE 1 Synthesis and Characterization of Star 1, Si[CH₂ CH₂Si(OC₂ H₅)₃ ]₄

To a mixture of 55.596 g (0.338 mol) of triethoxysilane and 10 drops(approximately 0.3 ml) of Pt catalyst was added 5.219 g (0.038 mol) oftetravinylsilane dropwise over a period of 1 hour. The temperature ofthe reaction mixture was controlled so as to not exceed 35° C. After theaddition, the solution was heated to 90° C. for 6 hours, then cooled andstirred at room temperature for 18 hours. The excess triethoxysilane wasremoved in vacuo at 60° C. Proton NMR of the product showed someresidual vinyl groups. An additional 11.842 g (0.0720 mol) oftriethoxysilane and 4 drops of Pt catalyst was added to the crudemixture and heated to 90° C. for 6 hours. Cooling to room temperatureand workup as described above yielded 26.75 g (88%) of a clear liquiddetermined to be mostly Si[CH₂ CH₂ Si(OC₂ H₅)₃ ]₄. Purity was found tobe 91% by K⁺ IDS mass spectroscopy and >75% by supercritical fluidchromatography (SFC). K⁺ IDS MS (m/e) 831 (M+39, 100%), 667 (H₂ C═CH)Si[CH₂ CH₂ Si(OC₂ H₅)₃ ]₃ +39, 8.6%) . 13C NMR(C₆ D₆) 3,57 (SiCH₂), 4.05(SiCH₂), 19.0 (CH₃), 59.0 (SiOCH₂). Small amounts of --SiCH (CH₃)Si(OC₂H₅)₃ groups due to Markovnikov (or reverse-hydrosilation) addition (1.0,9.0 ppm) were observed. Anal: Calcd for C₃₂ H₇₆ Si₅ O₁₂ C, 48.45; H,9.65; Si, 17.70. Found: C, 47.72; H, 9.59; Si, 17.37.

EXAMPLE 2 Synthesis and Characterization of Star 2, ((CH₃)₄ (C₂ H₅ O)₃SiCH₂ CH₂)₄ (SiO)₄

To a stirred mixture of 2.85 g (0.0083 mol) of ((CH₃)(CH₂ ═CH) SiO)₄ and8.15 g (0.0496 mol) of triethoxysilane was added 14 drops (ca 0.4 ml) ofPt catalyst. The resulting solution was heated to 100° C. for 2.5 hours,cooled and stirred at room temperature for 18 hours. The excess HSi(OC₂H₅)₃ was removed in vacuo and workup as described previously yielded aclear liquid identified as ((CH₃)((C₂ H₅ O)₃ SiCH₂ CH₂) SiO)₄.Impurities were mainly the di- and tri-substituted products as noted byK⁺ IDS MS. ¹³ C NMR(C₆ D₆) -0.901 ((CH₃)Si), 2.98 (SiCH₂), 9.30 (SiCH₂),19.01 (CH₃), 58.99 (SiOCH₂). K⁺ IDS MS (m/e) 1039 (M+39, 100 %), 875(3-arm product+39, 52%), 711 (2-arm product+39, 3%). Anal. Calcd for C₃₆H₈₈ Si₈ O₁₆ : C, 43.16; H, 8.85. Found: C, 42.12; H, 8.65.

EXAMPLE 3 Synthesis and Characterization of Star 3, Si(OSi(CH₃)₂ CH₂ CH₂Si(OC₂ H₅)₃)₄

To a stirred mixture of 3.039 g (0.0092 mol) of Si(OSi(CH₃)₂ H)₄ and10.024 g (0.05278 mol) of vinyltriethoxysilane was added 14 drops (ca0.4 ml) of Pt catalyst. The resulting solution was stirred for 2 hours,heated to 90° C. for 4 hours, cooled and stirred at room temperature for18 hours. The excess (CH₂ ═CH)Si(OC₂ H₅)₃ was removed in vacuo andworkup as described previously yielded a clear liquid identified asSi(OSi(CH₃)₂ CH₂ CH₂ Si(OC₂ H₅)₃)₄. Impurity levels were on the order of5% or less. ¹³ C NMR(C₆ D₆) -0.43 ((CH₃)Si), 3.19 (SiCH₂), 10.17(SiCH₂), 19.09 (CH₃), 58.86 (SiOCH₂). K⁺ IDS MS (m/e) 1128 (M+39, 100%).Anal. Calcd for C₄₀ H₁₀₀ Si₉ O₁₆ : C, 44.08; H, 9.25; Si, 23.19. Found:C, 44.66; H, 9.31; Si, 22.46.

EXAMPLE 4 Synthesis and Characterization of Star 4, Si(OCH₂ CH₂ CH₂Si(OC₂ H₅)₃)₄

A mixture of 3.12 g (0.0118 mol) of Si(OCH₂ CH═CH₂)₄, 11.028 g (0.0671mol) of HSi(OC₂ H₅)₃ and 14 drops of Pt catalyst was stirred at 25° C.for 2 hours and then heated to 90° C. for 4 hours. The solution wascooled, and the volatiles removed in vacuo. Workup as described aboveyielded 6.49 g of a clear liquid identified as Si(OCH₂ CH₂ CH₂ Si(OC₂H₅)₃)₄. ¹³ C NMR (C₆ D₆) 7.39 (SiCH₂), 18.97 (CH₃), 26.93 (CH₂), 58.89(SiO CH₂ CH₃), 66.55 (SiCH₂). K⁺ IDS MS (m/e) 952 (M+39, 100%). Anal.Calcd for C₃₆ H₈₄ Si₅ O₁₆ : C, 47.37; H, 9.27; Si, 15.37. Found: C,46.32; H, 9.10; Si, 16.06.

EXAMPLE 5 Synthesis and Characterization of Star 5, ((C₂ H₅ O)₃ SiCH₂CH₂)₂ (CH₃)SiOSi(CH₃)(CH₂ CH₂ Si(OC₂ H₅)₃)₂

To a stirred solution of 2.12 g (0.0101 mol) of ((CH₂ ═CH)₂ (CH₃)Si)₂ Oand 14 drops of Pt catalyst was added 7.93 g (0.0483 mol) of HSi(OC₂H₅)₃ via a syringe over a period of 1 hour. The mixture was heated to90° C. for 4 hours, then cooled to room temperature. The volatiles wereremoved in vacuo and the reaction product was worked up as describedabove yielding 3.80 g of a liquid identified as ((C₂ H₅ O)₃ SiCH₂ CH₂)₂(CH₃)SiOSi(CH₃)(CH₂ CH₂ Si(OC₂ H₅)₃)₂. Small amounts of impurities (<5%)were noted in the NMR corresponding to the tri-substituted product. ¹³ CNMR(C₆ D₆) -2.01 (CH₃ Si), 3.27 (SiCH₂), 8.32 (SiCH₂), 19.02 (CH₃),58.92 (SiOCH₂). K⁺ IDS MS (m/e) 905 (M+39, 100%), 743 (3-arm product+39,25%). Anal. Calcd for C₃₄ H₈₂ Si₆ O₁₃ : C, 47.07; H, 9.53; Si, 19.43.Found: C, 45.69; H, 9.40; Si, 19.40.

EXAMPLE 6 Synthesis and Characterization of Star 6, (C₂ H₅ O)₃ SiCH₂ CH₂(CH₃)₂ SiC₆ H₄ Si(CH₃)₂ CH₂ CH₂ Si(OC₂ H₅)₃

A mixture of 2.91 g (0.0150 mol) of H(CH₃)₂ C₆ H₄ (CH₃)₂ H, 10.03 g(0.0527 mol) of (CH₂ ═CH) Si(OC₂ H₅)₃ and 14 drops of Pt catalyst wasstirred at 25° C. for 2 hours and then heated to 90° C. for hours. Thesolution was cooled, and the volatiles removed in vacuo. Workup asdescribed above yielded 11.6 g of a liquid identified as Star 6. ¹³ CNMR(C₆ D₆) -3.11 (SiCH₃), 3.85 (SiCH₂), 7.80 (SiCH₂), 19.0 (CH₃), 26.93(CH₂), 58.9 (SiO CH₂ CH₃), 133.7, 136.6, 140.2 (aromatics). K⁺ IDS MS(m/e) 614 (M+39, 100%). Anal. Calcd for C₂₆ H₅₄ Si₄ O₆ : C, 54.31; H,9.46. Found: C, 53.53; H, 9.40.

EXAMPLE 7 Synthesis and Characterization of Star 7, (C₂ H₅ O)₃ SiCH₂ CH₂(CH₃)₂ SiC₆ H₄ OC₆ H₄ Si(CH₃)₂ CH₂ CH₂ Si(OC₂ H₅)₃

A mixture of 4.32 g (0.0151 mol) of (H(CH₃)₂ C₆ H₄)₂ O, 10.02 g (0.0526mol) of (CH₂ ═CH)Si(OC₂ H₅)₃ and 14 drops of Pt catalyst was stirred at25° C. for 2 hours and then heated to 90° C. for 4 hours. The solutionwas cooled, and the volatiles removed in vacuo. The resulting brownliquid was stirred over activated charcoal and filtered yielding 3.59 gof a clear liquid identified as Star 7. ¹³ C NMR(C₆ D₆) -2.93 (SiCH₃),3.89 (SiCH₂), 7.99 (SiCH₂), 19.06 (CH₃), 58.94 (SiO CH₂ CH₃), 119.2,133.8, 136.0, 158.9 (aromatics). Anal. Calcd for C₃₂ H₅₈ Si₄ O₇ : C,57.61; H, 8.76. Found: C, 57.03; H, 8.77.

EXAMPLE 8 Synthesis and Characterization of Star 8, (C₂ H₅ O)₃ SiCH₂ CH₂(CH₃)₂ SiOSi(CH₃)₂ CH₂ CH₂ Si(OC₂ H₅)₃

A solution consisting of 2.01 g (0.0150 mol) of (H(CH₃)₂ Si)₂ O, 10.01 g(0.0526 mol) of (CH₂ ═CH)Si(OC₂ H₅)₃ and 14 drops of Pt catalyst wasstirred at 25° C. for hours and then heated to 90° C. for 4 hours. Thesolution was cooled, and the volatiles removed in vacuo. Workup asdescribed above yielded 10.67 g of a clear liquid identified as Star 8.Small impurities (about were noted in the NMR spectra. ¹³ C NMR(C₆ D₆)0.22 (SiCH₃), 3.24 (SiCH₂), 10.41 (SiCH₂), 18.88 (CH₃), 58.95 (SiO CH₂CH₃). K⁺ IDS MS (m/e) 553 (M+39, 45%)

EXAMPLE 9 Synthesis and Characterization of Star 9, (C₂ H₅ O)₃ SiCH₂ CH₂(CH₃)₂ SiCH₂ CH₂ Si(CH₃)₂ CH₂ CH₂ Si(OC₂ H₅)₃

To a mixture consisting of 10.50 g (0.0552 mol) of (CH₂ ═CH)Si(OC₂ H₅)₃and 14 drops of Pt catalyst was added 3.72 g (0.0254 mol) of (H(CH₃)₂SiCH₂)₂ over a 30 min period. The temperature was kept around 35° C.during the addition. The mixture was then heated to 90° C. for 6 hours.After cooling, the volatiles removed in vacuo yielding 10.39 g of aclear liquid identified as Star 9. Some minor impurities were noted inthe NMR spectra. ¹³ C NMR (C₆ D₆) -3.89 (SiCH₃), 3.82 (SiCH₂), 6.71(SiCH₂), 7.46 (SiCH₂), 19.07 (CH₃), 58.95 (SiO CH₂ CH₃). K⁺ IDS MS (m/e)565 (M+39, 100%). Anal. Calcd for C₂₂ H₅₄ Si₄ O₆ : C, 50.14; H, 10.33.Found: C, 50.10; H, 10.35.

The reaction was performed in a manner similar to Star 9 using 10.03 g(0.0527 mol) of (CH₂ ═CH)Si(OC₂ H₅)₃, 2.89 g (0.0096 mol) of((CH₃)(H)SiO)₅ and 14 drops of Pt catalyst. Workup yielded 8.66 g of aclear liquid identified as Star 10. ¹³ C NMR (C₆ D₆) -0.75 (SiCH₃), 3.12(SiCH₂), 9.48 (SiCH₂), 19.05 (CH₃), 58.95 (SiO CH₂ CH₃). K⁺ IDS MS (m/e)1290 (M+39, 100%). Anal. Calcd for C₄₅ H110Si₁₀ O₂₀ : C, 43.16; H, 8.85.Found: C, 43.15; H, 8.79.

EXAMPLE 11 Synthesis and Characterization of Star 12, ((CH₃)₄ (C₂ H₅ O)₃SiCH₂ CH₂ CH₂)₄ (SiO)₄

The reaction was performed in a manner similar to Star 9 using 10.04 g(0.0491 mol) of (CH₂ ═CHCH₂)Si(OC₂ H₅)₃, 2.32 g (0. 0097 mol) of((CH₃)(H)SiO)₄ and 14 drops of Pt catalyst. Workup yielded 7.74 g of aliquid identified as Star 12. ¹³ C NMR(C₆ D₆), 0.131 (SiCH₃), 15.57(SiCH₂), 17.64 (SiCH₂), 19.03 (CH₃), 22.07 (CH₂), 58.79 (SiO CH₂ CH₃).K⁺ IDS MS (m/e) 1095 (M+39, 100%). Anal. Calcd for C₄₀ H₉₆ Si₈ O₁₆ : C,45.42; H, 9.15. Found: C, 46.35; H, 9.26.

EXAMPLE 12 Synthesis and Characterization of Star 13, ((CH₃)₅ (C₂ H₅ O)₃SiCH₂ CH₂ CH₂)₅ (SiO)₅

The reaction was performed in a manner similar to Star 9 using 8.49 g(0.0416 tool) of (CH₂ ═CHCH₂)Si(OC₂ H₅)₃, 2.45 g (0.0082 mol) of((CH₃)(H)SiO)₅ and 14 drops of Pt catalyst. Workup yielded 5.94 g of aliquid identified as Star 12. ¹³ C NMR(C₆ D₆) 0.269 (SiCH₃), 15.74(SiCH₂), 17.79 (SiCH₂), 19.04 (CH₃), 22.40 (CH₂), 58.83 (SiO CH₂ CH₃).K⁺ IDS MS (m/e) 1359 (M+39, 100%). Anal. Calcd for C₅₀ H₁₂₀ Si₁₀ O₂₀ :C, 45.42; H, 9.15. Found: C, 46.41; H, 9.23.

EXAMPLE 13 Synthesis and Characterization of Star 14, Si(OSi(CH₃)₂ CH₂CH₂ CH₂ Si(OC₂ H₅)₃)₄

To a stirred mixture of 10.04 g (0.0491 mol) of allyltriethoxysilane and14 drops (ca 0.4 ml) of Pt catalyst was added 3.17 g (0.0096 mol) ofSi(OSi(CH₃)₂ H)₄ over a period of 1 hour. The resulting solution washeated to 90° C. for 4 hours, cooled and stirred at room temperature for18 hours. The excess (CH₂ ═CHCH₂)Si(OC₂ H₅)₃ was removed in vacuo andworkup as described previously yielded 8.84 g of a liquid identified asSi(OSi(CH₃)₂ CH₂ CH₂ CH₂ Si(OC₂ H₅)₃)₄. ¹³ C NMR(C₆ D₆) -0.14 ((CH₃)Si),15.04 (SiCH₂), 16.74 (SiCH₂), 17.80 (CH₃), 22.13 (--CH₂ --), 58.86(SiOCH₂). K⁺ IDS MS (m/e) 1183 (M+39, 100%). Anal. Calcd for C₄₄ H₁₀₈Si₅ O₁₆ : C, 46.11; H, 9.50. Found: C, 46.28; H, 9.55.

EXAMPLE 14 Synthesis and Characterization of Star 15, (C₂ H₅ O)₃ SiCH₂CH₂ CH₂ (CH₃)₂ SiC₆ H₄ Si(CH₃)₂ CH₂ CH₂ CH₂ Si(OC₂ H₅)₃

To a stirred mixture of 9.56 g (0.0468 mol) of allyltriethoxysilane and14 drops (ca 0.4 ml) of Pt catalyst was added 2.94 g (0.0151 mol) ofH(CH₃)₂ SiC₆ H₄ Si(CH₃)₂ H over a period of 30 min. The resultingsolution was heated to 90° C. for 4 hours, cooled and stirred at roomtemperature for 18 hours. The excess (CH₂ ═CHCH₂)Si(OC₂ H₅)₃ was removedin vacuo and workup as described previously yielded 9.63 g of a liquididentified as Star 15. ¹³ C NMR (C₆ D₆) -2.43 ((CH₃)Si), 15.96 (SiCH₂),18.53 (SiCH₂), 19.00 (CH₃), 20.42 (--CH₂ --), 58.82 (SiOCH₂). K⁺ IDS MS(m/e) 641 (M+39, 100%).

EXAMPLE 15 Synthesis and Characterization of Star 17, (CH.sub.3)Si(OSi(CH₃)₂ CH₂ CH₂ Si(OC₂ H₅)₃)₃

A stirred mixture of 10.01 g (0.0609 mol) of triethoxysilane, 14 drops(ca 0.4 ml) of Pt catalyst and 3.35 g (0.0123 mol) of (CH₃)Si(OSi(CH₃)₂CH═CH₂)₃ was stirred at 25° C. for 2 hours and then heated to 90° C. for4 hours, cooled and stirred at room temperature for 18 hours. The excessHSi(OC₂ H₅)₃ was removed in vacuo yielding 15.46 g of a clear liquididentified as (CH₃)Si(OSi(CH₃)₂ CH₂ CH₂ Si(OC₂ H₅)₃)₃. ¹³ C NMR (C₆ D₆)0.11 ((CH₃)Si), 3.16 (SiCH₂), 10.30 (SiCH₂), 18.82 (CH₃), 58.76(SiOCH₂). Anal. Calcd for C₃₁ H₇₈ Si₇ O₁₂ : C, 44.35; H, 9.36. Found: C,44.99; H, 9.46

EXAMPLE 16 Synthesis and Characterization of Star 18, Si(CH₂ CH₂Si(OCH₃)₃)₄

To a stirred mixture of 2.21 g (0.0162 tool) of tetravinylsilane and 7drops (ca 0.4 ml) of Pt catalyst was added 12.016 g (0.0096 mol) oftrimethoxysilane over a period of 1 hour. The resulting solution washeated to 90° C. for 4 hours, cooled and stirred at room temperature for18 hours. The excess HSi[O(CH₃)]₃ was removed in vacuo yielding 9.78 gof a liquid identified as Si(CH₂ CH₂ Si(OCH₃)₃)₄. Column chromatographyof the Star product resulted in partial hydrolysis of Si-CCH₃ groups.Some Markovnikov addition products, similar to those observed in Star 1,were also seen in the NMR. ¹³ C NMR (C₆ D₆) 2.69 (SiCH₂), 3.34 (SiCH₂),50.8 (SiOCH₃). K⁺ IDS MS (m/e) 663 (M+39, 90%), 617 ((CH₃)₂ O+39, 100%).

EXAMPLE 17 Gel from Star 1 with water/ethanol

1.868 g Star 1 was dissolved in 2.42 g anhydrous ethanol to give ahomogeneous solution. 0.510 g of water containing 0.040 g 0.1N HCl wasadded to this solution over a period of two minutes with moderatestirring. The ratio of water to Si(OR) groups was 1.00. The solutionremained clear and formed a clear gel after 23 hours. The wet gel wasdried initially at room temperature and atmospheric pressure, then at atemperature of 120° C. and a pressure of 10⁻⁵ torr. The dry gel waspulverized and subjected to pore size analysis by the BET methodadsorption analysis using nitrogen at -196° C. in accordance with ASTMstandard C₁₀₆₉ -86. The sample did not show a significant weight gaindue to nitrogen adsorption after 4 hours. Small pieces of the dried gelwere submerged in water and observed under a microscope. No evidence offracture or gas liberation was observed. Taken together, theseobservations indicate the sample did not possess open porosity.

EXAMPLE 18 Gel from Star 3 with HCOOH

1.562 g Star 3 was added to 1.86 g 96% formic acid with stirring. Themixture formed a clear solution after several seconds. The ratio of acidto Si(OR) groups was 2.26. The solution was transferred into apolyethylene vial and allowed to stand at room temperature. The sampleformed a transparent gel after 13 min. The contents of the vial wereallowed to dry via slow evaporation of the liquid component of the gel.The material was fully dried after two weeks and had formed an intactsmooth right cylinder which was translucent. The dried gel remainedintact after impact from a 150 g pestle dropped from a heights of 2-3cm. Comparably sized pieces of conventional sol-gel glasses wereconsistently fractured from the same impact exposure.

EXAMPLE 19 Attenuation of Gelation Rate for Star 3 with Tetrahydrofuran

1.183 g Star 3 was dissolved in 3.20 g tetrahydrofuran (THF). 0.526 g96% formic acid was added to above solution with stirring. The ratio ofacid to Si(OR) groups was 0.842. The solution was transferred into afluoropolymer vial and allowed to stand at room temperature. The sampleformed a transparent gel after 19 days.

EXAMPLE 20 Dip and Flow coats from Star 1 HCOOH/Tetrahydrofuran

3.36 g Star 1 was combined with 12.37 g tetrahydrofuran and 2.35 gformic acid per Example 4. The ratio of acid to Si(OR) groups was 0.96.The solution (which gelled in four hours) was used to prepare coatingson glass slides via dip and flow coating techniques. Coatings made threehours after the reactants were mixed were transparent and crack-free.The flow coating was shown by surface profilometry to be 2.5 micrometersin thickness; the dip coating was 0.5 micrometers in thickness.

EXAMPLE 21 Gel from Star 1 with tetraethoxysilane in HCOOH; Gel rateenhancement

0.865 Star 1 was combined with 2.04 g tetraethoxysilane to give ahomogeneous solution which was added to 1.53 g HCOOH with stirring. Theresultant solution gelled in 8.3 minutes. The Star was 10 mole % of thetotal silanes present. The ratio of acid to silanes was 2.93. At thesame molar ratio of HCOOH/silane, pure tetraethoxysilane requires ca. 18hours for gelation.

EXAMPLE 22 High Surface Area Gel from Star 1 with tetraethoxysilane

1.064 g Star 1 combined with 2.492 g tetraethoxysilane to give ahomogeneous solution which was added to 3.161 g HCOOH with stirring. Theresultant solution gelled in 1.5 minutes. The Star was 10 mole % of thetotal silanes present. At the same molar ratio of HCOOH/silane (4.96),pure tetraethoxysilane requires ca. 2 hours for gelation. The wet gelwas dried under vacuum at 60° C. within minutes of its preparation, thenat a temperature of 120° C. and a pressure of 10⁻⁵ torr. The dry gel wasthen subjected to porosity analysis per the procedure in Example 17. Thesurface area was determined to be 629 m² /g, with an average pore sizeof approximately 2.0 nanometers. The surface area value is higher thanthose observed by this procedure for gels made from tetraethoxysilanewithout the star gel precursor.

EXAMPLE 23 Gel from star 10 with HCOOH/methylene chloride

1.92 g of star gel precursor 10 was dissolved in 4.05 g reagent grademethylene chloride to give a homogeneous solution. 0.785 g of 96% formicacid was added dropwise to this solution over a period of one minutewith moderate stirring. The ratio of acid to Si(OR) groups was 0.71. Theresultant solution remained clear and later formed a clear gel onstanding overnight. Several drops of the solution were placed betweentwo 25×75 mm glass microscope slides so as to form a thin continuouslayer between the slides. After several hours, the slides were firmlybonded together and could not be separated or moved relative to eachother by moderate amounts of force, illustrating the adhesive nature ofthe gel.

EXAMPLE 24 Synthesis and Characterization of Star 11 Si(CH₂ CH₂ CH₂Si(OC₂ H₅)₃)₄ {(a); m=0; k=0; h=0; all R's=H}

To a stirred solution of 5.28 g (0.0321 mol) of HSi(OC₂ H₅)₃ and 5 dropsof Pt catalyst solution in 20 mL of hexane was added 0.626 g (0.0033mol) of Si(CH₂ CH=CH₂)₄ over a two minute period. The mixture wasrefluxed for 1 hr and stirred at 25° C. for 60 hr. The unreactedvolatiles were removed in vacuo, and the crude mixture was worked up asdescribed previously yielding 1.78 g (64%) of Si(CH₂ CH₂ CH₂ Si(OC₂H₅)₃)₄. ¹³ C NMR(C₆ D₆) 16.46, 17.89, 18.65 (SiCH₂), 19.05 (CH₃), 58.83(SiOCH₂ CH₃). K⁺ IDS MS (m/e) (M+39, 100%).

EXAMPLE 25 Synthesis and Characterization of Star 16 (C₂ H₅ O)₃ SiCH₂CH₂ (CF₂)₆ CH₂ CH₂ Si(OC₂ H₅)₃ {(j); p=6; k=0, h=0, all R's=H}

To a stirred mixture of 0.041 g (0.120 mmol) of Co₂ (CO)₈, 0.029 g(0.234 mmol) of P(OCH₃)₃ in 1 mL of toluene was added 2.48 g (6.503mmol) of CH₂ ═CH(CF₂)₆ CH═CH₂ and 5.34 g (32.5 mmol) of HSi(OC₂ H₅)₃.The mixture was stirred at room temperature for 4 days and an extra 3.22g of HSi(OC₂ H₅)₃ was added to ensure completion of the reaction. Afterstirring for 11 days the solution was heated at 60° C. for 6 hr; andstirred at room temperature for another 7 days until there was noremaining vinyl groups observed in the NMR. Standard workup provided5.19 g of a dark brown solution. The remaining color was removed by theaddition of activated charcoal. The ratio of CH₂ ═CH(CF₂)₆ CH₂ CH₂Si(OC₂ H₅).sub. 3 to (C₂ H₅ O)₃ SiCH₂ CH₂ (CF₂)₆ CH₂ CH₂ Si(OC₂ H₅)₃ inthe product mixture was found to be 74% to 26%. K⁺ IDS MS (m/e) 557(monosubstituted, M+39, 100%), 721 (M+39, 65%). GC/MS (CI-isobutane)exact mass for C₁₆ H₂₂ O₃ SiF₁₂ +H, calcd m/e 519. 1225, found m/e519.1263, exact mass for C₂₂ H₃₈ O₆ Si₂ F₁₂ +H, calcd m/e 683.2093,found m/e 683.2144.

EXAMPLE 26 Synthesis and Characterization of Cl₃ SiCH₂ CH₂ (CF₂)_(n) CH₂CH₂ SiCl₃ (n=6, 10) {(j); p=6, 10; k=0, h=0, all R's=H; Q=Cl}

To a 10 mL pressure vessel was added 1.28 g (3.36 mmol) of CH₂ ═CH(CF₂)₆CH=CH₂, 1.32 mL (13.08 mmol) of HSiCl₃ and one drop of Pt catalyst. Thereaction vessel was sealed and heated at 100° C. for 48 hr. The vesselwas cooled, and the excess HSiCl₃ was removed in vacuo leaving a 1.622 g(77% yield) of a white solid. GC analysis showed that the solid is asingle compound. 1H NMR (C₆ D₆) 1.05 (m, 2H, SiCH₂), 1.98 (m, 2H,SiCH₂). The preparation of Cl₃ SiCH₂ CH₂ (CF₂)₁₀ CH₂ CH₂ SiCl₃ wasperformed in a similar manner using 3.66 g (6.66 mmol) of CH₂ ═CH(CF₂)₆CH═CH₂, 2.71 g (20.02 mmol) of HSiCl₃. A temperature of 120° C. for 48hr was needed to ensure complete reaction. Workup yielded 1.63 g (30%)of Cl₃ SiCH₂ CH₂ (CF₂)₁₀ CH₂ CH₂ SiCl₃ as the only product. 1H NMR(C₆D₆) 1.02 (m, 2H, SiCH₂), 1.91 (m, 2H, SiCH₂). The conversion of Cl₃SiCH₂ CH₂ (CF₂)_(n) CH₂ CH₂ SiCl₃ to (C₂ H₅ O)₃ SiCH₂ CH₂ (CF₂).sub. nCH₂ CH₂ Si(OC₂ H₅)₃ can be accomplished by known literature methodsusing ethanol.

EXAMPLE 27 Synthesis and Characterization of Star 16 (C₂ H₅ O)₃ SiCH₂CH₂ (CF₂)₆ CH₂ CH₂ Si(OC₂ H₅)₃ {(j); p=6, k=0, h=0, all R's=H}

A stirred solution containing 0.259 g (0.424 mmol) of [ICH₂ CH₂ (CF₂)₃]₂ dissolved in 10 mL of ether was cooled to -78° C. To this was added1.01 mL (1.71 mmol) of tert-butyl lithium. The resulting mixture wasstirred for 1.5 h and 1.90 mL (8.518 mmol) of Si(OC₂ H₅)₄ was added. Themixture was warmed to room temperature and stirred for 90 hr. Thevolatiles were removed in vacuo yielding 0.054 g (18%) of a brownresidue. GC/MS (CI-isobutane) shows the residue is mainly (C₂ H₅ O)₃SiCH₂ CH₂ (CF₂)₆ CH₂ CH₂ Si(OC₂ H₅)₃ (calcd m/e/ 683.2156, found (C₂ H₅O)₃ SiCH₂ CH₂ (CF₂)₆ CH₂ CH₂ Si(OC₂ H₅)₃ (But).

EXAMPLE 28 Synthesis and Characterization of Star 21 (C₂ H.sub. 5 O)₃(CH₂)₆ (CF₂)₁₀ (CH₂)₆ Si(OC₂ H₅)₃ {(j); p=10, k=4, h=0, all R's=H}

A solution consisting of 5.00 g (7.51 mmol) of {CH₂ ═CH(CH₂)₄ (CF₂)₅ ]₂,5.55 g (33.8 mmol) of HSi(OC₂ H₅)₃, 10 drops of Pt catalyst in 20 mL oftoluene was heated at 90° C. for 6 hr, and stirred at room temperaturefor 10 hr. The volatiles were removed in vacuo and normal workupprovided 6.45 g (86%) of (C₂ H₅ O)₃ Si(CH₂)₆ (CF₂)₁₀ (CH₂)₆ Si(OC₂ H₅)₃as an off-white waxy solid. ¹³ C NMR(C₆ D₆) 11.50, 20.71, 23.53, 29.27,33.12 (CH₂), 31.58 (t, CH₂ CF₂, 2J(C-F)=22 hz), 18.99 (SiOCH₂ CH₃),58.91 (SiOCH₂ CH₃). K⁺ IDS MS (m/e) 1033 (M+39, 100%).

EXAMPLE 29 Synthesis and Characterization of Star 19 1,3,5-((C₂ H₅ O)₃SiCH₂ CH₂ (CH₃)₂ Si)₃ C₆ H₃ {Z=CH₃ ; k=0, h=0, all R's=H}

To 3.01 g (9.12 mmol) of 1,3,5-((C₂ H₅ O)₃ SiCH₂ CH₂ (CH₃)₂ Si)₃ C₆ H₃and eight drops of Pt catalyst was added 5.54 g (33.7 mmol) of HSi(OC₂H₅)₃. The resulting mixture was heated to 90° C. for 6 hr and stirred atroom temperature for 16 hr. Standard workup provided 5.83 g (78%) of1,3,5-((C₂ H₅ O)₃ SiCH₂ CH₂ (CH₃)₂ Si)₃ C₆ H₃ as the sole product. ¹³ CNMR(C₆ D₆) -2.91 (CH₃ Si), 4.05 (CH₂), 7.99 (CH₂), 19.03 (SiOCH₂ CH₃),58.97 (SiOCH₂ CH₃), 137.96, 140.32 (aromatic). K⁺ IDS MS (m/e) 861(M+39, 100%).

EXAMPLE. 30 Synthesis and Characterization of Star 20 1,2,4-((C₂ H.sub.5 O)₃ SiCH₂ CH₂)₃ C₆ H₃ {k=0, h=0, all R's=H}

A mixture containing 3.206 g (0.0198 mol) of 1,2,4-trivinylcyclohexane,26.32 g (0.160 mol) of HSi(OC₂ H₅)₃ and 10 drops of Pt catalyst wasstirred at room temperature. Oxygen was bubbled through the solution for5 min., and then the solution was heated to reflux for 7 hr, cooled andstirred at room temperature for 16 hr. Standard workup provided 11.68 g(90%) of 1,2,4-((C₂ H₅ O)₃ SiCH₂ CH₂)₃ C₆ H₃ as a clear liquid. ¹³ CNMR(C₆ D₆) 5.98 to 42.72 (many peaks, CH₂, CH), 18.18 (SiOCH₂ CH₃),17.97 (disubst, SiOCH₂ CH₃), 58.17 (SiOCH₂ CH₃), 58.15 (disubst, SiOCH₂CH₃). K⁺ IDS MS (m/e) 693 (M+39, 100%). A small amount of disubstitutedproduct, (CH₂ ═CH)((C₂ H₅ O)₃ SiCH₂ CH₂)₂ C₆ H₉, was also observed 529(M+39, 26%).

EXAMPLE 31 Formation of Very Low Surface Energy Glass

Approximately 0.35 g (0.35 mmol) Star 21 (C₂ H₅ O)₃ Si(CH₂)₆ (CF²)₁₀(CH₂)₆ Si(OC₂ H₅)₃, was dissolved in 1.00 g reagent gradetetrahydrofuran to give a homogeneous solution. Approximately 0.25 g(5.43 mmol) of 96% formic acid was added dropwise to this solution overa period of one minute with moderate stirring. The resultant solutionremained clear and formed a clear yellow gel on standing overnight. Theyellow color is believed due to residual platinum catalyst from thesynthesis of the Star. The gel was dried over the course of several daysat room temperature into a clear yellow glassy disk weighing 0.278 g. Noevidence for open porosity in the glass was obtained when it wassubmerged in fluids which wet the surface well.

The surface energy of the glass was assessed by measuring contact anglesfor several different liquids via the sessile drop method (A. W.Anderson, Physical Chemistry of Surfaces, 4th ed., Wiley-Interscience,NY, 1982, pp. 341-342). After these measurements, the sample was exposedto the silylating agent bistrimethylsilyl acetamide (a 10% solution byweight in acetonitrile) for 15 min. at room temperature so as to convertresidual high energy silanol (Si-OH) surface groups into Si--O--SiMe₃groups. The contact angle measurements were then repeated. The very highcontact angles for water and methylene iodide indicate a highlyhydrophobic low energy surface, especially after the silylationreaction. The surface energy was calculated to be 15.2 mN/meter,substantially less than that for poly(tetrafluoroethylene) [Teflon®].The surface energy was calculated according to the equation

    cos θ=-1+2(γ.sub.1.sup.d γ.sub.s.sup.d).sup.1/2/ γ.sub.1.sup.d

where the superscript d refers to the dispersive component of the liquidor solid free energies g, and is listed in Table II. The equation, whichis quite accurate in predicting contact angles of both polar andnon-polar liquids on polymers, is based on the assumptions that thereversible work of adhesion can be approximated by its dispersivecomponent, and that the solid/vapor free energy is negligible. See B.Sauer, J. Adhesion Sci. Tech., 6, 955 (1992) for details.

                  TABLE II                                                        ______________________________________                                        Fluoroglass Sample Surface Energy Data                                                      As        After                                                               Generated Silylation                                                                             PTFE*                                        ______________________________________                                        Contact angle water                                                                           90°  123°                                                                            110°                              (advancing)                                                                   Contact angle CH.sub.2 I.sub.2                                                                Not Measured                                                                              90°                                                                             83°                               Contact angle n-hexadecane                                                                    0           11°                                                                             40°                               Surface energy mN/meter                                                                       ca. 30        15.2     23.9                                   ______________________________________                                         *Poly(tetrafluoroethylene)                                               

What is claimed is:
 1. An inorganic/organic composition of the idealizedempirical formula (II):

    X(SiO.sub.1.5).sub.n                                       (II)

wherein n is an integer greater than or equal to 2; and X is at leastone flexible organic link selected from the group consisting of:(a) R¹_(m) SiY_(4-m) ; (b) ring structures ##STR29## (c) R¹ _(m) Si(OSi(CH₃)₂Y)_(4-m) ; (d) R¹ _(m) Si(OY)_(4-m) ; (e) CH₃ SiY₂ --O--SiY₂ CH₃ ; (f)Y(CH₃)₂ Si--C₆ H₄ --Si(CH₃)₂ Y; (g) O[--C₆ H₄ --Si(CH₃)₂ Y]₂ ; (h)O[Si(CH₃)₂ Y]₂ ; (i) Y(CH₃)₂ SiCH₂ --CH₂ Si(CH₃)₂ Y; (j) Y₃ SiOSiY₃ ;(k) Y₃ Si(CH₂)_(b) SiY₃ ; (l) Y₃ SiC₆ H₄ SiY₃ ; (m) substituted benzeneselected from the group consisting of:(i) C₆ H₃ (SiZ_(3-a) Y_(a))₃ ;(ii) C₆ H₂ (SiZ_(3-a) Y_(a))₄ ; (iii) C₆ H(SiZ_(3-a) Y_(a))₅ ; and (iv)C₆ (SiZ_(3-a) Y_(a))₆ ; and (n) substituted cyclohexane selected fromthe group consisting of:(i) 1,2-C₆ H₁₀ (Y)₂ ; 1,3-C₆ H₁₀ (Y)₂ ; 1,4-C₆H₁₀ (Y)₂ ; (ii) 1,2,4-C₆ H₉ (Y)₃ ; 1,2,3-C₆ H₉ (Y)₃ ; 1,3,5-C₆ H₉ (Y)₃ ;(iii) 1,2,3,4-C₆ H₈ (Y)₄ ; 1,2,4,5-C₆ H₈ (Y)₄ ; 1,2,3,5-C₆ H₈ (Y)₄ ;(iv) 1,2,3,4,5-C₆ H₇ (Y)₅ ; and (v) C₆ H₆ (Y)₆ ;wherein: Z is an alkylgroup of 1 to 4 carbon atoms, 3,3,3-trifluoropropyl, aralkyl, or aryl; Yis (CR² R³)_(k) CR⁴ R⁵ CR⁶ R⁷ (CR⁸ R⁹)_(h) --; R¹ is alkyl of 1 to about8 carbon atoms or aryl; R² to R⁹ are each independently hydrogen, alkylof 1 to about 8 carbon atoms or aryl, provided that at least one of R⁴to R⁷ is hydrogen; m is 0, 1 or 2; k and h are each independently aninteger from 0 to 10, provided that at least one of k or h is zero; a is1, 2 or 3; p is an even integer from 4 to 10; and b is an integer from 1to
 10. 2. A process for the preparation of the composition of formula(II)

    X(SiO.sub.1.5).sub.n                                       (II)

wherein n is an integer greater than or equal to 2; and X is at leastone flexible organic link selected from the group consisting of:(a) R¹_(m) SiY_(4-m) ; (b) ring structures ##STR30## (c) R¹ _(m) Si(OSi(CH₃)₂Y)_(4-m) ; (d) R¹ _(m) Si(OY)_(4-m) ; (e) CH₃ SiY₂ --O--SiY₂ CH₃ ; (f)Y(CH₃)₂ Si--C₆ H₄ --Si(CH₃)₂ Y; (g) O[--C₆ H₄ --Si(CH₃)₂ Y]₂ ; (h)O[Si(CH₃)₂ Y]₂ ; (i) Y(CH₃)₂ SiCH₂ --CH₂ Si(CH₃)₂ Y; (j) Y(CF₂)_(p) Y,provided that when p is 6, Y is other than ethylene; (k) Y₃ SiOSiY₃ ;(l) Y₃ Si(CH₂)_(b) SiY₃ ; (m) Y₃ SiC₆ H₄ SiY₃ ; (n) substituted benzeneselected from the group consisting of:(i) C₆ H₃ (SiZ_(3-a) Y_(a))₃ ;(ii) C₆ H₂ (SiZ_(3-a) Y_(a))₄ ; (iii) C₆ H(SiZ_(3-a) Y_(a))₅ ; and (iv)C₆ (SiZ_(3-a) Y_(a))₆ ; and (o) substituted cyclohexane selected fromthe group consisting of:(i) 1,2-C₆ H₁₀ (Y)₂ ; 1,3-C₆ H₁₀ (Y)₂ ; 1,4-C₆H₁₀ (Y)₂ ; (ii) 1,2,4-C₆ H₉ (Y)₃ ; 1,2,3-C₆ H₉ (Y)₃ ; 1,3,5-C₆ H₉ (Y)₃ ;(iii) 1,2,3,4-C₆ H₈ (Y)₄ ; 1,2,4,5-C₆ H₈ (Y)₄ ; 1,2,3,5-C₆ H₈ (Y)₄ ;(iv) 1,2,3,4,5-C₆ H₇ (Y)₅ ; and (v) C₆ H₆ (Y)₆ ;wherein: Z is an alkylgroup of 1 to 4 carbon atoms, 3,3,3-trifluoropropyl, aralkyl, or aryl; Yis (CR² R³)_(k) CR⁴ R⁵ CR⁶ R⁷ (CR⁸ R⁹)_(h) --; R¹ is alkyl of 1 to about8 carbon atoms or aryl; R² to R⁹ are each independently hydrogen, alkylof 1 to about 8 carbon atoms or aryl, provided that at least one of R⁴to R⁷ is hydrogen; m is 0, 1 or 2; k and h are each independently aninteger from 0 to 10, provided that at least one of k or h is zero; a is1, 2 or 3; p is an even integer from 4 to 10; and b is an integer from 1to 10 comprising: (A) mixing at least one compound of formula (III):

    X(SiQ.sub.3).sub.n                                         (III)

wherein: Q is alkoxy of 1 to about 8 carbon atoms, acyloxy of 1 to about8 carbon atoms; n is an integer greater than or equal to 2; and X is atleast one flexible organic link selected from the group consistingof:(a) R¹ _(m) SiY_(4-m) ; (b) ring structures ##STR31## (c) R¹ _(m)Si(OSi(CH₃)₂ Y)_(4-m) ; (d) R¹ _(m) Si(OY)_(4-m) ; (e) CH₃ SiY₂--O--SiY₂ CH₃ ; (f) Y(CH₃)₂ Si--C₆ H₄ --Si(CH₃)₂ Y; (g) O[--C₆ H₄--Si(CH₃)₂ Y]₂ ; (h) O[Si(CH₃)₂ Y]₂ ; (i) Y(CH₃)₂ SiCH₂ --CH₂ Si(CH₃)₂Y; (j) Y(CF₂)_(p) Y, provided that when p is 6, Y is other thanethylene; (k) Y₃ SiOSiY₃ ; (l) Y₃ Si(CH₂)_(b) SiY₃ ; (m) Y₃ SiC₆ H₄ SiY₃; (n) substituted benzene selected from the group consisting of:(i) C₆H₃ (SiZ_(3-a) Y_(a))₃ ; (ii) C₆ H₂ (SiZ_(3-a) Y_(a))₄ ; (iii) C₆ H(SiZ_(3-a) Y_(a))₅ ; and (iv) C₆ (SiZ_(3-a) Y_(a))₆ ; and (o)substituted cyclohexane selected from the group consisting of:(i) 1,2-C₆H₁₀ (Y)₂ ; 1,3-C₆ H₁₀ (Y)₂ ; 1,4-C₆ H₁₀ (Y)₂ (ii) 1,2,4-C₆ H₉ (Y)₃ ;1,2,3-C₆ H₉ (Y)₃ ; 1,3,5-C₆ H₉ (Y)₃ ; (iii) 1,2,3,4-C₆ H₈ (Y)₄ ;1,2,4,5-C₆ H₈ (Y)₄ ; 1,2,3,5-C₆ H₈ (Y)₄ ; (iv) 1,2,3,4,5-C₆ H₇ (Y)₅ ;and (v) C₆ H₆ (Y)₆ ;wherein: Z is an alkyl group of 1 to 4 carbon atoms,3,3,3-trifluoropropyl, aralkyl, or aryl; Y is (CR² R³)_(k) CR⁴ R⁵ CR⁶ R⁷(CR⁸ R⁹)_(h) --; R¹ is alkyl of 1 to about 8 carbon atoms or aryl; R² toR⁹ are each independently hydrogen, alkyl of 1 to about 8 carbon atomsor aryl, provided that at least one of R⁴ to R⁷ is hydrogen; m is 0, 1or 2; k and h are each independently an integer from 0 to 10, providedthat at least one of k or h is zero; a is 1, 2 or 3; p is an eveninteger from 4 to 10; and b is an integer from 1 to 10,in the presenceof water a solvent and a catalyst, or in the presence of at least onecarboxylic acid having a maximum pKa value about 4.0 and containing from0 to 20 mole % water and an optional solvent; (B) maintaining themixture resulting from step (A) at a temperature within the range ofabout 0°-100° C.; and (C) isolating the resulting inorganic/organiccomposition of formula (II).
 3. A method for modifying a sol-gel glassto generate a sol-gel glass that can tolerate increased drying rates andshows lower brittleness comprising:(A) combining a star gel precursor offormula (III):

    X(SiQ.sub.3).sub.n                                         (III)

wherein: Q is alkoxy of 1 to about 8 carbon atoms, acyloxy of 1 to about8 carbon atoms, of halogen; n is an integer greater than or equal to 2;and X is at least one flexible organic link selected from the groupconsisting(a) R¹ _(m) SiY_(4-m) ; (b) ring structures ##STR32## (c) R¹_(m) Si(OSi(CH₃)₂)_(4-m), (d) R¹ _(m) Si(OY)_(4-m) ; (e) CH₃ SiY₂--O--SiY₂ CH₃ ; (f) Y(CH₃)₂ Si--C₆ H₄ --Si(CH₃)₂ Y; (g) O[--C₆ H₄--Si(CH₅)₂ Y]₂ ; (h) O[Si(CH₃)₂ Y]₂ ; (i) Y(CH₃)₂ SiCH₂ --CH₂ Si(CH₃)₂Y; (j) Y(CF₂)_(p) Y; (k) Y₃ SiOSiY₃ ; (l) Y₃ Si(CH₂)_(b) SiY₃ ; (m) Y₃SiC₆ H₄ SiY₃ ; (n) substituted benzene selected from the groupconsisting of:(i) C₆ H₃ (SiZ_(3-a) Y_(a))₃ ; (ii) C₆ H₂ (SiZ_(3-a)Y_(a))₄ ; (iii) C₆ H(SiZ_(3-a) Y_(a))₅ ; and (iv) C₆ (SiZ_(3-a) Y_(a))₆; and (o) substituted cyclohexane selected from the group consistingof:(i) 1,2-C₆ H₁₀ (Y)₂ ; 1,3-C₆ H₁₀ (Y)₂ ; 1,4-C₆ H₁₀ (Y)₂ (ii) 1,2,4-C₆H₉ (Y)₃ ; 1,1,3-C₆ H₉ (Y)₃ ; 1,3,5-C₆ H₉ (Y)₃ ; (iii)₁,2,3,4 -C₆ H₈ (Y)₄; 1,2,4,5-C₆ H₈ (Y)₄ ; 1,2,3,5-C₆ H₈ (Y)₄ ; (iv)₁,2,3,4,5 -C₆ H₇ (Y)₅ ;and (v) C₆ H₆ (Y)₆ ;wherein: Z is an alkyl group of 1 to 4 carbon atoms,3,3,3-trifluoropropyl, aralkyl, or aryl; Y is (CR² R³)_(k) CR⁴ R⁵ CR⁶ R⁷(CR⁸ R⁹)_(h) --; R¹ is alkyl of 1 to about 8 carbon atoms or aryl; R² toR⁹ are each independently hydrogen, alkyl of 1 to about 8 carbon atomsor aryl, provided that at least one of R⁴ to R⁷ is hydrogen; m is 0, Ior 2; k and h are each independently an integer from 0 to 10, providedthat least one of k or h is zero; a is 1, 2 or 3; p is an even integerfrom 4 to 10; and b is an integer from i to 10;with an inorganicalkoxide sol-gel precursor; (B) mixing in water with a solvent and acatalyst, or mixing a carboxylic acid having a maximum pk_(a) value ofabout 4 optionally in the presence of a solvent; and (C) drying.
 4. Amethod for coating a substrate comprising reacting the star gelprecursor of formula (III):

    X(SiQ.sub.3).sub.n                                         (III)

wherein: Q is alkoxy of 1 to about 8 carbon atoms, acyloxy of 1 to about8 carbon atoms, or halogen; n is an integer greater than or equal to 2;and X is at least one flexible organic link selected from the groupconsisting of:(a) R¹ _(m) Si(Y)_(4-m) ; (b) ring structures ##STR33##(c) R¹ _(m) Si(OSi(CH₃)₂ Y)_(4-m), (d) R¹ _(m) Si(OY)_(4-m),(e) CH₃ SiY₂--O--SiY₂ CH₃ ; (f) Y(CH₃)₂ Si--C₆ H₄ --Si(CH₃)₂ Y; (g) O[--C₅ H₄--Si(CH₃)₂ Y]₂ ; (h) O[Si(CH₃)₂ Y]₂ ; (i) Y(CH₃)₂ SiCH₂ --CH₂ Si(CH₃)₂Y; (j) Y(CF₂)_(p) Y; (k) Y₃ SiOSiY₃ ; (l) Y₃ Si(CH₂)_(b) SiY₃ ; (m) Y₃SiC₆ H₄ SiY₃ ; (n) substituted benzene selected from the groupconsisting of:(i) C₆ H₃ (SiZ_(3-a) Y_(a))₃ ; (ii) C₆ H₂ (SiZ_(3-a)Y_(a))₄ ; (iii) C₆ H(SiZ_(3-a) Y_(a))₅ ; and (iv) C₆ (SiZ_(3-a) Y_(a))₆; and (o) substituted cyclohexane selected from the group consistingof:(i) 1,2-C₆ H₁₀ (Y)₂ ; 1,3-C₆ H₁₀ (Y)₂ ; 1,4-C₆ H₁₀ (Y)₂ (ii) 1,2,4-C₆H₉ (Y)₃ ; 1,2,3-C₆ H₉ (Y)₃ ; 1,3,5-C₆ H9(Y)₃ ; (iii) 1,2,3,4-C₆ H₈ (Y)₄; 1,2,4,5-C₆ H₈ (Y)₄ ; 1,2,3,5-C₆ H₈ (Y)₄ ; (iv) 1,2,3,4,5-C₆ H₇ (Y)₅ ;and (v) C₆ H₆ (Y)₆ ;wherein, Z is an alkyl group of 1 to 4 carbon atoms,3,3,3-trifluoropropyl, aralkyl or aryl; Y is (CR² R³)_(k) CR⁴ R⁵ CR⁶ R⁷(CR⁸ R⁹)_(h) --; R¹ is alkyl of 1 to about 8 carbon atoms or aryl; R² toR⁹ are each independently hydrogen, alkyl of 1 to about 8 carbon atomsor aryl, provided that it least one of R⁴ to R⁷ is hydrogen; m is 0, 1or 2; X and h are each independently an integer from 0 to 10, providedthat at least one of k or h is zero; and a is 1, 2 or 3; p is an eveninteger from 4 to 10; and b is an integer from 1 to 10;in the presenceof water, a solvent and a catalyst, or in the presence of a strongcarboxylic acid having a maximum pk_(a) value of about 4, optionally inthe presence of a solvent; dipping the substrate in the resultingmixture; removing the coated Substrate from the mixture and drying thecoating to generate a substrate coated with a composition of formula II

    X(SiO.sub.1.5).sub.n                                       (II)

wherein n is an integer greater than or equal to 2; and X is at leastone flexible organic link selected from the group consisting of:(a) R¹_(m) SiY_(4-m) ; (b) ring structures ##STR34## (c) R¹ _(m) Si(OSi(CH₅)₂Y)_(4-m), (d) R¹ _(m) Si(OY)_(4-m), (e) CH₃ SiY₂ --O--SiY₂ CH₃ ; (f)Y(CH₃)₂ Si--C₆ H₄ --Si(CH₃)₂ Y; (g) O[--C₆ H₄ --Si(CH₃)₂ Y]₂ ; (h)O[Si(CH₅)₂ Y]₂ ; (i) Y(CH₃)₂ SiCH₂ --CH₂ Si(CH₃)₂ Y; (j) Y(CF₂)_(p) Y,provided that when p is 6, Y is other than ethylene; (k) Y₃ SiOSiY₃ ;(l) Y₃ Si(CH₂)_(b) SiY₃ ; (m) Y₃ SiC₆ H₄ SiY₃ ; (n) substituted benzeneselected from the group consisting of:(i) C₆ H₃ (SiZ_(3-a) Y_(a))₃ ;(ii) C₆ H₂ (SiZ_(3-a) Y_(a))₄ ; (iii) C₆ H(SiZ_(3-a) Y_(a)); ₅ ; and (o)substituted cyclohexane selected from the group consisting of:(i) 1,2-C₆H₁₀ (Y)₂ ; 1,3-C₆ H₁₀ (Y)₂ ; 1,4-C₆ H₁₀ (Y)₂ ; (ii) 1,2,4-C₆ H₉ (Y)₃ ;1,2,3-C₆ H₉ (Y)₃ ; 1,3,5-C₆ H₉ (Y)₃ ; (iii) 1,2,3,4-C₆ H₈ (Y)₄ ;1,2,4,5-C₆ H₈ (Y)₄ ; 1,2,3,5-C₆ H₈ (Y)₄ ; (iv) 1,2,3,4,5-C₆ H₇ (Y)₅ ;and (v) C₆ H₆ (Y)₆ ;wherein: Z is an alkyl group of 1 to 4 carbon atoms,3,3,3-trifluoropropyl, aralkyl, or aryl; Y is (CR² R³)_(k) CR⁴ R⁵ CR⁶ R⁷(CR⁸ R⁹)_(h) --; R¹ is alkyl of 1 to about 8 carbon atoms or aryl; R² toR⁹ are each independently hydrogen, alkyl of 1 to about 8 carbon atomsor aryl, provided that at least one of R⁴ to R⁷ is hydrogen; m is 0, 1or 2; k and h are each independently an integer from 0 to 10, providedthat at least one of k or h is zero; a is 1, 2 or 3; p is an eveninteger from 4 to 10; and b is an integer from 1 to
 10. 5. Aninorganic/organic gel of the idealized empirical formula:

    X(SiO.sub.1.5).sub.n

wherein: n is an integer greater than or equal to 2; and X is at leastone flexible organic link of the formula:

    Y(CF.sub.2).sub.p Y,

wherein: Y is (CR² R³)_(k) CR⁴ R⁵ CR⁶ R⁷ (CR⁸ R⁹)_(h) --; R² to R⁹ areeach independently hydrogen, alkyl or 1 to about 8 carbon atoms or aryl,provided that at least one of R⁴ to R⁷ is hydrogen; k and h are eachindependently an integer from 4 to 10, provided that at least one of kor h is zero; and p is an even integer from 4 to 10.